Production system for corrugated carboard sheet

ABSTRACT

A system for fabricating a corrugated board sheet fabricated includes warp status information obtaining means ( 6, 6 A- 6 H,  7, 7 A,  7 B,  8, 8 A- 8 H,  240   a,    240   b,    241   a,    241   b ) for obtaining warp status information concerning status of the warp of the corrugated board sheet fabricated by a corrugated-board fabrication machine ( 1 ); running-state information obtaining means ( 5, 5 A- 5 H) for obtaining running state information concerning a running state of the corrugated-board fabrication machine ( 1 ); control variable calculating means ( 4, 4 A- 4 H) for calculating a control variable of a particular control factor that affects the warp of the corrugated board sheet and that is one among control factors used to control the corrugated-board fabrication machine ( 1 ) based on the warp status information of the corrugated board sheet and the running state information of the corrugated-board fabrication machine ( 1 ); and control means ( 5, 5 A- 5 H) for controlling the particular control factor using the control variable calculated by the control variable calculating means ( 4, 4 A- 4 H).

TECHNICAL FIELD

The present invention relates to a system for fabricating a corrugatedboard sheet, which system includes a preheater, a double facer, a warpdetection apparatus, a counter of corrugated board sheets and a warpcorrection system and the like for a corrugated-board fabricationmachine.

BACKGROUND OF THE INVENTION

A corrugated board sheet is fabricated by the following process in whicha liner (a bottom liner) is glued to a corrugated medium web withadhesive to form a single-face web, gluing the medium web of thesingle-face web to the other liner (a top liner) and then cutting thefabricated corrugated board into an appropriate length with a cut-offdevice. During the process, a web (each of a bottom liner, a top liner,a single-face web, and a corrugated board) is heated by a preheaterexemplified by a bottom liner preheater, a single-face web preheater anda top liner preheater, and heated by a double facer, and is pasted by asingle facer and a glue machine. At that time, an inappropriate level ofheat or amount of glue causes defects in a resultant corrugated boardsheet, e.g., width-direction upward or downward warp (hereinafter simplycalled width-direction warp) or inferior gluing. For example, anexcessive moisture content of a bottom liner causes a convex surfacetoward a top liner when being dried; and an excessive moisture contentof the top liner causes a convex surface toward the bottom liner whenbeing dried.

Further, during the fabrication process, if a transfer-direction(hereinafter also called travel-direction) tension of a top liner or asingle-face sheet is out of the appropriate range so that there is asignificant difference in travel-direction tension between a top linerand a single-face web, the resultant corrugated board sheet has a defectsuch as travel-direction upward/downward warp (hereinafter simply calledtravel-direction warp) or inferior gluing.

Still further, when a travel-direction tension distribution (hereinaftersimply called tension) of each web is varied in the web-width directionas compared with an appropriate distribution, a resultant corrugatedboard sheet has twist warp.

Generally, an optimum tension distribution (i.e., a tension distributionthat causes no twist warp) is uniform over the web width direction. But,if fiber fabricating a web is inclined with respect to the traveldirection of the web, the resulting corrugated board sheet has twistwarp in spite of uniform a tension distribution in the web-widthdirection because the tension distribution is relatively varied in thewidth direction compared to the optimum tension distribution.

Conventionally, in order to correct warp of the above types, an operatorvisually checks warp status of a corrugated board sheet, appropriatelyselects one or more control factors that affect type of warp on thebasis of experience or know-how and manually adjusts the individualcontrol factors.

However, such an adjustment manner depending on experience or know-howmay lead to inconsistency in quality of resultant corrugated boardsheets depending on different operators's skill levels. Additionally,the same operator may repeat the adjustment over and over and may makeerrors in the adjustment operation leading to difficulties in obtainingconstant product quality. Further, since there are a great number ofcontrol factors to be adjusted and adjustment variables of each controlfactor are determined considering current values, the adjustmentoperation is complex and time-consuming.

Engineers have been working on development of a technology that inhibitswarp of the corrugated board sheets and thereby improves quality ofresultant corrugated board sheets by matrix control that automaticallyadjusts each control factor such as wrap amount around each preheater,gap amounts in the single facer and the glue machine and pressureapplied by the double facer, based on production state information suchas a base-board composition, basis weight of the base board, width ofcorrugated board sheet, flute and the like so that width-direction warpis corrected. With such a system, a matrix prepared beforehand can dealwith fabrication of corrugated board sheets even if a base board havinga special composition or a specially processed base board is used forthe fabrication.

During an exceptional production state in which a top liner and a bottomliner have the same base board composition and have different moisturecontents or base boards of the same type are different in moisturecontent, even if each control factor is automatically adjusted in theabove system, temperature of a web does not reach a predeterminedappropriate temperature and, as a result, the resultant corrugated boardsheets may have width-direction warp.

For this reason, warp caused under such an exceptional production stateshould be corrected by an operator visually checking warp status of thecorrugated board sheet and dealing with the warp on the basis ofexperience and/or know-how.

In order to deal with travel-direction warp, Japanese Patent ApplicationLaid-Open (Kokai) No. HEI 10-128881 discloses a technique in whichappropriate tensions to be applied to a top liner and/or a bottom linerare calculated on the basis of a detection signal from a warp detectionapparatus and tension adjusting apparatus adjusts the tensions thereofto those calculated.

However, since this technique simply controls one or more particularcontrol factors, each of which has previously been selected as a tensionadjusting apparatus, in accordance with warp status of a corrugatedboard sheet, adjustment of each control factor is constant irrespectiveof warp amount. Therefore, adjustment for only the above selectedcontrol factors takes a long time to correct warp of large extent and,in extreme cases, there is a possibility that travel-direction warpcannot be corrected.

A double facer presses a top liner, which is piled together with asingle-face web, against hotplates to heat the single-face web and thetop liner whereby the single-face web is heated through the top linerand is joined to the top liner.

A conventional double facer has hotplates, each of which is in a singleform across the width of a web, so that the double facer cannot dissolvewidth-direction unevenness of the moisture contents (i.e., unevenness oftemperatures) of a single-face web and/or a top liner transferred intothe double facer. The moisture-content unevenness or the temperatureunevenness may therefore tend to cause width-direction S-shape warp(hereinafter, simply called S-shape warp), that is, a sheet curling in awave-shape in the width direction.

FIG. 86 schematically shows a front sectional view (seen from the webtraveling direction) of a conventional preheater. The preheater 300 isin the form of a heating roll to heat web being wrapped around the rollduring rotation thereof in synchronization with the travel of the web.The preheater 300 includes a cylindrical shell 301 into which vapor issupplied in order to heat web, axes 302 a and 302 b arranged at the bothends of the shell 301 and rotatably supported by bearings 303.

One axis 302 a takes the form of a pipe through which vapor for heatinga web is supplied into the inside of the shell 301. A drainpipe 304 ispassed into the shell 301 through the axis 302 a so that the vaporbecomes condensation and is drained from the shell 301 through the drainpipe 304.

Similar to the above-described conventional hotplates included in adouble facer, the conventional preheater is also in the form of a singleform across the web-width direction (perpendicular to the web traveldirection) and therefore cannot dissolve width-direction unevenness ofwater content (unevenness of temperature) of a base board (a top liner,a bottom liner, a medium web) transferred into a corrugated-boardfabrication machine. The above moisture-content unevenness andtemperature unevenness may sometimes cause a resultant corrugated boardsheet to have width-direction S-shape warp.

Japanese Patent Application Laid-Open (Kokai) No. HEI 9-131814 disclosesa technique to inhibit width-direction S-shape warp of a corrugatedboard sheet by dissolving width-direction unevenness of moisture contentof the web.

In this technique, a plurality of press rolls, which press web in theprocess of being transferred, are arranged along the width direction ofthe web upstream or downstream of a preheater roll around which the webis wrapped. Each of these press rolls can be attached or detached thetravel path of a web. Control for the position of each individual pressroll varies tension acting on individual portions of the web whichportions are arranged along the web width direction and also variespressure applied to each of the portions of the web toward the preheaterroll. It is thereby possible to vary a heat amount applied to each ofthe portions along the width direction and to dissolve water-contentunevenness whereupon occurrence of S-shape warp is inhibited.

However, this technique largely affects tension of a web, e.g.,variation in tension distribution in the width direction of the web,resulting in warp. There is a possibility that the S-shape warp cannotbe satisfactorily inhibited and that warp of another type may begenerated on a resultant corrugated board sheet.

As described above, an operator may correct warp of a corrugated boardsheet by visually checking warp status (warp type and warp amount) ofthe corrugated board sheet, selecting one or more corresponding factorsassociated with the warp status from the control factors on the basis ofexperience and know-how, and manually adjusting the selected factors.

A visual operator check, however, cannot quantitatively grasp a warpamount of a corrugated board sheet, so it is difficult to accuratelycorrect the warp of the corrugated board sheet as a result of such avisual check. Warp correction in this manner takes time until acorrugated board sheet of product quality can be obtained. Additionally,the operator has to continuously check status of corrugated board sheetsthat have been loaded.

In order to solve the above problem, an apparatus for quantitativelydetecting warp amount of a corrugated board sheet has been developed.There has not been developed a technique to quantitatively detect anamount of travel-direction warp or twist warp.

A double-face web, which has been cut by a cut-off device to serve as afinal product of a corrugated board sheet, is transferred from thecut-off device to a stacker by a conveyer and is stacked in the stacker.

In such a conventional corrugated-board fabrication machine, a countingroll that rotates following transfer of a double-face web is installedat a web transferring unit arranged upstream of the cut-off device. Thenumber of corrugated board sheets is counted on the basis of amount ofrotation of the counting roll.

The above counting roll, however, may be not able to obtain an exactnumber of fabricated corrugated board sheets because of slipping betweenthe counting roll and transferred double-face web.

Further, corrugated board sheets having large warp or inferior gluingmay sometimes be removed as being defective during transfer. If removalof defectives is carried out downstream of the counting roll, the numberof corrugated board sheets obtained by the counting roll is consequentlydifferent from the number of corrugated board sheets serving as finalproducts.

DISCLOSURE OF THE INVENTION

(1)

It is the first object of the present invention is to provide a systemfor correcting warp of a corrugated board sheet in which warp of acorrugated board sheet is accurately corrected with ease withoutdepending on the experience of an operator and know-how.

In order to attain the first object, there is provided a system forcorrecting warp of a corrugated board sheet (hereinafter simply calledsystem) comprising warp status information obtaining means,running-state information obtaining means, control variable calculatingmeans and control means, and correcting warp of a corrugated board sheetfabricated in the corrugated-board fabrication machine with theseelements. Further, the system may preferably comprise control factorselecting means.

Hereinafter is a description of each of the above elements in relationto (1-1) correction of width-direction warp, (1-2) correction oftravel-direction warp and (1-3) correction of twist warp.

(1-1) Correction of Width-Direction Warp of a Corrugated Board Sheet:

In order to accomplish the above first object, the system has thefollowing configuration (a) or (b) to deal with width-direction warp ofa corrugated board sheet.

(a)

The warp status information obtaining means obtains warp statusinformation concerning status (up/downward direction and largeness(extent) of warp) of the warp of the corrugated board sheet fabricatedby the corrugated-board fabrication machine. The manner of obtaininginformation may be carried out by manual input by an operator orautomatically. If manual input by an operator is performed, the systemmay preferably include selection means for receiving an operator'sselection for an arbitrary one from a plurality of candidates indicatingstatus of, for example, width-direction warp of a corrugated board sheetand obtains the selected candidate as information concerning status ofthe warp.

On the other hand, if the system automatically obtains the information,the system may preferably include, for example, imaging means forimaging a corrugated board sheet fabricated by the corrugated-boardfabrication machine and detection means for detecting the warp of thecorrugated board sheet on the basis of image data obtained by theimaging means so that the system obtains the data detected by thedetection means as information concerning status of the warp. In thiscase, for example, the imaging means images edges along the widthdirection of a corrugated board sheet fabricated by the corrugated-boardfabrication machine and the detection means detects width-direction warpof the corrugated board sheet based on the image data obtained by theimaging means, so that it is possible to correct the width-directionwarp.

Otherwise, the system may further comprise variation amount detectingmeans for detecting a vertical variation amount of a corrugated boardsheet and detection means for detecting warp of the corrugated boardsheet on the basis of information on the vertical variation amountobtained by the variation amount detecting means so that informationdetected by the detection means is regarded as information concerningstatus of the warp of the corrugated board sheet. In this case, forexample, the variation amount detecting means measures the variationamount along the direction of the width of the corrugated board sheetand the detection means detects width-direction warp of the corrugatedboard sheet based on the variation amount information obtained by thevariation amount detecting means, whereupon it is possible to correctthe width-direction warp.

The running-status information obtaining means obtains running stateinformation concerning a running state of the corrugated-boardfabrication machine. The running state information represents runningspeed, wrap amount of a web around each preheater, vapor pressureapplied to each preheater, gap amount of each pasting device, pressureapplied by and vapor pressure applied to a double facer, and/or amountof lubricant if the corrugated-board fabrication machine includes alubrication unit.

The control factor selecting means selects at least one particularcontrol factor from a plurality of control factors that affect watercontent of a bottom liner or a top liner in accordance with the warpstatus of the corrugated board sheet and an influence of each of theplurality of particular control factors on the warp. The particularcontrol factors are exemplified by control factors that control a heatamount applied to a bottom liner by bottom liner heating means, a glueamount applied to a medium web in a single facer, a heat amount appliedto a single-face web by single-face web heating means, a heat amountapplied to a top liner by top liner heating means, a glue amount appliedto the single-face web at a glue machine, or a heat amount applied to adouble-face web in a double facer.

Specifically, control factors for a heat amount applied to a web (abottom liner, a single-face web, a top liner) by corresponding heatingmeans (bottom liner heating means, single-face web heating means, topliner heating means) are a wrap amount of each web around acorresponding heating roll, which amount is adjusted by each wrap amountadjusting means, and/or vapor pressur applied to each heating roll.Further, in order to control a glue amount applied to a medium web inthe single facer, at least one of one or more gap amounts between rollsused during a procedure to apply glue to the medium web beingtransferred by a corrugated roll, which gap amounts are exemplified bythat between the corrugated roll and a pasting roll or between rollsincluded in a pasting unit can be determined as a control factor. Inorder to control a pasting amount applied to a single-face web in theglue machine, a gap amount between a pasting roll disposed along atravel path of the single-face web and the travel path can be determinedas a control factor. In relation to control over a heat amount appliedto a double-face web in the double facer, at least one item serving as acontrol factor is selected from pressure applied to one surface of thedouble-face web towards hotplates arranged along the travel path of thedouble-face web by a press unit, a vapor pressure applied to thehotplates, and a travel speed of the double-face web on the hotplates.

If the corrugated-board fabrication machine further includes a bottomliner lubrication unit to lubricate a bottom liner before or aftergluing a single-face web to a top liner in the double facer, and a topliner lubrication unit to lubricate a top liner, a lubrication amount toa bottom liner from the bottom liner lubrication unit and a lubricationamount to a top liner from the top liner lubrication unit may be addedto the particular control factors. The lubrication manner is exemplifiedby spraying water onto a web from a shower unit or by applying wateronto the web with a water-applying roll.

The control variable calculating means calculates a control variable ofthe particular control factor selected by the control factor selectingmeans based on the warp status information of the corrugated board sheetand the running state of the corrugated-board fabrication machine.

The control means controls the selected particular control factor usingthe control variable calculated by the control variable calculatingmeans. Specifically, the control means controls each actuator associatedwith the particular control factor such that the current value of theparticular control factor becomes the control variable calculated by thecontrol variable calculating means.

With this configuration, since a particular control factor that affectswarp of a corrugated board sheet is automatically controlled inaccordance with the warp status obtained by the warp status informationobtaining means, it is possible to accurately correct width-directionwarp of the corrugated board sheet with ease without depending on theexperience of an operator and the know-how. In particular, if theinformation obtaining means automatically obtains information,width-direction warp of a corrugated board sheet is automaticallycorrected during the entire process.

As a preferable feature, the control factor selecting means of thesystem sequentially selects particular control factors in accordancewith largeness of warp of a corrugated board sheet, considering apredetermined priority order. The extent of correction can therefore belarger in accordance with largeness of warp so that it is possible torapidly correct the warp of the corrugated board sheet. Especially, if aparticular control factor that more largely affects warp gets a higherpriority, warp correction can be further rapidly accomplished.

(b)

The warp status information obtaining means detects information(up/downward direction and largeness of warp) concerning status of warpof a corrugated board sheet, and includes moisture content measuringmeans for measuring moisture contents of a bottom liner and a top lineror parameters correlating with the moisture contents and detection meansfor detecting the warp of the corrugated board sheet on the basis ofdata obtained by the moisture content measuring means. The warp statusinformation obtaining means regards data obtained by the detection meansas the warp status information.

The moisture content measuring means may perform the measurement at theentrance of a double facer in which a single-face web, which has beenformed by joining a medium web to a bottom liner, is glued to a topliner to thereby fabricate a double-face web, or at the exit of thedouble facer. For example, the moisture content measuring means is inthe form of one or more moisture sensors or temperature sensors.Preferable measurement by the moisture content measuring means iscarried out along the width direction of the bottom and the top liners.

The running-state information obtaining means obtains informationconcerning a running state of the corrugated-board fabrication machine.The running-state information concerns a running speed, a wrap amount ofa web around each preheater, vapor pressure applied to each preheater, agap amount of each pasting device, pressure applied by and vaporpressure applied to the double facer, and/or an amount of lubricant ifthe corrugated-board fabrication machine includes a lubrication unit.

The control factor selecting means selects at least one particularcontrol factor from a plurality of control factors that affect a watercontent of a bottom liner or a top liner in accordance with the warpstatus of the corrugated board sheet and an influence of each of theplurality of particular control factors on the warp. The particularcontrol factors are exemplified by control factors that control a heatamount applied to a bottom liner by bottom liner heating means, a glueamount applied to a medium web in a single facer, a heat amount appliedto a single-face web by single-face web heating means, a heat amountapplied to top liner by top liner heating means, a glue amount appliedto the single-face web at a glue machine, or a heat amount applied to adouble-face web in the double facer.

The control variable calculating means calculates a control variable ofthe particular control factor selected by the control factor selectingmeans based on the warp status information of the corrugated board sheetand the running state of the corrugated-board fabrication machine.

The control means controls the selected particular control factor usingthe control variable calculated by the control variable calculatingmeans. Specifically, the control means controls each actuator associatedwith the particular control factor such that the current value of theparticular control factor becomes the control variable calculated by thecontrol variable calculating means.

With this configuration, since a particular control factor that affectswarp of a corrugated board sheet is automatically controlled inaccordance with the warp status obtained by the warp status informationobtaining means, it is possible to automatically and accurately correctwidth-direction warp of the corrugated board sheet with ease withoutdepending on the experience of an operator and know-how.

As a preferable feature, the control factor selecting means of thesystem sequentially selects particular control factors in accordancewith largeness of warp of a corrugated board sheet, considering apredetermined priority order. The extent of correction can therefore belarger in accordance with the largeness of warp so that it is possibleto rapidly correct warp of the corrugated board sheet. Especially, if aparticular control factor that has amore significant effects on warpgets a higher priority, warp correction can be further rapidlyaccomplished.

In particular, since the moisture content measuring means measures themoisture contents of a single-face web and a top liner at the entranceor the exit (preferably the entrance) of the double facer, and controlin order to correct width-direction warp of a corrugated board sheet isexecuted based on the detected contents, the control can be performed atan early stage and it is therefore possible to correct warp even ifshort-run fabrication (short order) is performed.

Further, when the moisture content measuring means is configured so asto measure moisture content along the width direction of the bottomliner and the top liner, it is possible to precisely judge warp statusbased on the measurement result even if both the bottom liner and thetop liner have variation in moisture content.

(1-2) Correction of Travel Direction-Warp of a Corrugated board sheet:

The warp status information obtaining means obtains warp statusinformation concerning status (an up/downward direction and largeness oftravel-direction warp) of the warp of the corrugated board sheetfabricated by the corrugated-board fabrication machine. The manner ofobtaining information may be carried out by a manual input of anoperator or automatically. If manual input by an operator is performed,the warp status information obtaining means may preferably includeselection means for receiving an operator's selection for an arbitraryone from a plurality of candidates indicating status of, for example,travel-direction warp of a corrugated board sheet, and warp statusinformation obtaining means obtains the selected candidate asinformation concerning status of the travel-direction warp.

On the other hand, if the warp status information obtaining meansautomatically obtains the information, the warp status informationobtaining means may preferably include, for example, imaging means forimaging edges along the travel direction of a corrugated board sheetfabricated by the corrugated-board fabrication machine, and detectionmeans for detecting the travel-direction warp on the basis of image dataobtained by the imaging means so that the warp status informationobtaining means obtains the data detected by the detection means asinformation concerning status of the travel-direction warp of thecorrugated board sheet.

Otherwise, the warp status information obtaining means may comprisevariation amount detecting means for detecting a vertical variationamount of a corrugated board sheet along the travel direction of thesheet and detection means for detecting travel-direction warp of thecorrugated board sheet on the basis of information of the verticalvariation amount obtained by the variation amount detecting means sothat information detected by the detection means is regarded asinformation concerning status of the travel-direction warp of thecorrugated board sheet.

The running-state information obtaining means obtains informationconcerning a running state of the corrugated-board fabrication machine.The information concerning running-state information is exemplified byrunning speed, brake force of each braking device and/or wrap amount ofa web around a wrap roll.

The control factor selecting means selects at least one particularcontrol factor from a plurality of particular control factors thataffect travel-direction tension of a bottom liner or a top liner inaccordance with the warp status of the corrugated board sheet and aninfluence of each of the plurality of particular control factors ontravel-direction warp. The particular control factors are braking forcethat a braking device applies to traveling single-face web or top liner,and a wrap amount of a single-face web or a top liner around a wrap rollfor at least one of the single-face web and the top liner in the form ofa sheet. A wrap amount is adjusted by wrap amount adjusting means.

The control means controls the selected particular control factor usingthe control variable calculated by the control variable calculatingmeans. Specifically, the control means controls each actuator associatedwith the particular control factor such that the current value of theparticular control factor becomes the control variable calculated by thecontrol variable calculating means.

With this configuration, since a particular control factor that affectswarp of a corrugated board sheet is automatically controlled inaccordance with the travel-direction warp status obtained by the warpstatus information obtaining means, it is possible to accurately andeffectively correct travel-direction warp of the corrugated board sheetwith ease without depending on the experience of an operator and theknow-how. In particular, if the information obtaining meansautomatically obtains information, the entire correction oftravel-direction warp of a corrugated board sheet is automaticallyexecuted.

As a preferable feature, the control factor selecting means of thesystem sequentially selects particular control factors in accordancewith largeness of warp of a corrugated board sheet, considering apredetermined priority order. The extent of correction can therefore belarger in accordance with the largeness of warp so that it is possibleto rapidly correct warp of the corrugated board sheet. Especially, if aparticular control factor that more largely affects warp gets a higherpriority, warp correction can be further rapidly accomplished.

(1-3) Correction of Twist Warp of a Corrugated Board Sheet:

The warp status information obtaining means obtains warp statusinformation concerning status (pattern and extent of twist warp) of thetwist warp of the corrugated board sheet fabricated by thecorrugated-board fabrication machine. The manner of obtaininginformation may be carried out by manual input by an operator orautomatically. If manual input by an operator is performed, the wrapstatus information obtaining means may preferably include selectionmeans for receiving the operator's selection for an arbitrary one from aplurality of candidates indicating status of, for example, twist warp,and wrap status information obtaining means obtains the selectedcandidate as information concerning status of the twist warp.

On the other hand, if the wrap status information obtaining meansautomatically obtains the information, the wrap status informationobtaining means may preferably include, for example, imaging means forimaging the four corners of a corrugated board sheet fabricated by thecorrugated-board fabrication machine and detection means for detectingtwist warp of the corrugated board sheet on the basis of image dataobtained by the imaging means so that the system obtains the datadetected by the detection means as information concerning status of thetwist warp of the corrugated board sheet.

Otherwise, the system may further comprise variation amount detectingmeans for detecting vertical variation amounts at points near the fourcorners of a corrugated board sheet and detection means for detectingtwist warp of the corrugated board sheet on the basis of information ofthe vertical variation amounts obtained by the variation amountdetecting means so that information detected by the detection means maybe regarded as information concerning status of the twist warp of thecorrugated board sheet.

The running-status information obtaining means obtains running stateinformation of the corrugated-board fabrication machine. The runningstate information concerns running speed, tilt angle of press means ofthe double facer in relation to the web-travel direction,web-width-direction distribution of press force of the press means, theheights of both axis ends of a wrap roll arranged upstream of the doublefacer, and distribution of suction force of a suction brake along theweb width direction for a single-face web.

The control variable calculating means calculates a control variable ofa particular control factor based on the warp status information of acorrugated board sheet and the running state of the corrugated-boardfabrication machine. A particular control factor is a control factorthat affects web-width-direction distribution of travel-directiontension of a top liner.

For example, if the corrugated-board fabrication machine includes adouble facer to glue the single-face web to the top liner, and thedouble facer includes hotplates and pressing means arranged along thetravel direction of webs, which pressing means is divided into aplurality of pieces and presses the single-face web and the top liner tothe hotplates. At the same time, if at least one piece of the pressingmeans has a structure able to vary the tilt angle thereof in relation tothe web width direction, the tilt angle of the pressing means is alsodefined as a particular control factor.

Alternatively, if at least one piece of the pressing means is able tocontrol web-width-direction distribution of pressure applied to thesingle-face web and the top liner, the web-width-direction distributionof the pressure is included in the particular control factors.

Further alternatively, if a wrap roll around which the single-face webis wrapped is disposed upstream of the double facer and the heights ofthe both axis ends of the wrap roll can be individually controlled, theheight of each axis end of the wrap roll is defined as the particularcontrol factor.

Still further alternatively, when the corrugated-board fabricationmachine includes a suction brake that applies suction force serving asbrake force for the travel of the single-face web and the suction brakeis able to control the web-width-direction distribution of the suctionforce, the web-width-direction distribution of the suction force isincluded in the particular control factors.

The control means controls the selected particular control factor usingthe control variable calculated by the control variable calculatingmeans. Specifically, the control means controls each actuator associatedwith the particular control factor such that the current value of theparticular control factor becomes the control variable calculated by thecontrol variable calculating means.

With this configuration, since a particular control factor that affectswarp of a corrugated board sheet is automatically controlled inaccordance with the twist warp status obtained by the warp statusinformation obtaining means, it is possible to accurately correct twistwarp of a corrugated board sheet with ease without depending on theexperience of an operator and the know-how. In particular, if theinformation obtaining means automatically obtains information, twistwarp of a corrugated board sheet is fully-automatically corrected.

Preferably, the system comprises control factor selecting means toselect at least one of a plurality of particular control factors thataffect web-width-direction distribution of travel-direction tension of asingle-face web or a top liner on the basis of status of twist warp of acorrugated board sheet and influence of each particular control factoron the twist warp of a corrugated board sheet.

As a preferable feature, the control factor selecting means of thesystem sequentially selects particular control factors in accordancewith largeness of warp of a corrugated board sheet, considering apredetermined priority order. The extent of correction can therefore belarger in accordance with the largeness of warp so that it is possibleto rapidly correct warp of the corrugated board sheet. Especially, if aparticular control factor that has greater effect on warp gets a higherpriority, warp correction can be further rapidly accomplished.

(2)

The second object of the present invention is to provide a system forfabricating a corrugated board sheet that satisfies predeterminedquality without depending on the experience of an operator and theknow-how.

In order to attain the second object, the system for fabricating acorrugated board sheet of the present invention (hereinafter simplycalled the system) comprises running-state information obtaining means,production-state information obtaining means, control variablecalculating means, quality information detecting means, optimum runningcondition information retaining means and control means, which are to bedescribed below. A feature of the system is inhibiting width-directionwarp of a corrugated board sheet fabricated in a corrugated-boardfabrication machine with the above elements.

The running-state information obtaining means obtains informationconcerning a running state of the corrugated-board fabrication machine.The running-state information concerns a running speed, a wrap amount ofa web around each preheater, vapor pressure applied to each preheater, agap amount of each pasting device, pressure applied by and vaporpressure applied to a double facer, and/or an amount of lubricant whenthe corrugated-board fabrication machine includes a lubrication unit.

The production-state information obtaining means obtains productionstate information concerning a production state in the corrugated-boardfabrication machine. The production state information represents abase-board composition, a basis weight of the base board, the width of acorrugated board sheet, a flute and the like.

The quality information detecting means detects that a corrugated boardsheet fabricated in the corrugated-board fabrication machine satisfies apredetermined quality, and is, for example, in the form of a qualityinformation in putting means for inputting the information aboutsatisfaction of the predetermined quality of the corrugated board sheetas the result of judgment by an operator. Here, quality means the warpstatus of the corrugated board sheet, for example, so that satisfactionof the predetermined quality means that the corrugated board sheet hasno warp.

The control variable calculating means calculates a control variable ofeach control factor based on the running state information obtained bythe running-state information obtaining means and the production-stateinformation obtained by the production-state information obtainingmeans.

The optimum running-condition information retaining means retains, ifthe quality information detecting means detects that the corrugatedboard sheet satisfies the predetermined quality, a portion of therunning state information obtained by the running-state informationobtaining means which portion is associated with a particular controlfactor that affects the predetermined quality, so that the portion ofthe running-state information serves as an optimum running condition ofthe corrugated-board fabrication machine when the quality informationdetecting means detects that the corrugated board sheet satisfies thepredetermined quality.

For example, if the predetermined quality of a corrugated board sheetrepresents warp status of the corrugated board sheet, the typicalparticular control factors are control factors that affect moisturecontent of a bottom liner or a top liner. The particular control factorsare exemplified by control factors that control a heat amount applied toa bottom liner by bottom liner heating means, a glue amount applied to amedium web in a single facer, a heat amount applied to a single-face webby single-face web heating means, a heat amount applied to a top linerby top liner heating means, a glue amount applied to the single-face webat a glue machine, or a heat amount applied to a double-face web in adouble facer.

Specifically, concerning about control factors for a heat amount appliedto a web (a bottom liner, a single-face web, a top liner) bycorresponding heating means (bottom liner heating means, single-face webheating means, and top liner heating means), the particular controlfactors are exemplified by a wrap amount of each web around acorresponding heating roll, which amount is adjusted by each wrap amountadjusting means, and/or vapor pressure applied to each heating roll.Further, concerning about control of a glue amount applied to a mediumweb in the single facer, the particular control factors are exemplifiedby at least one of the gap amounts between rolls used during a procedureto apply glue to a medium web being transferred by a corrugated roll.The gap amount is exemplified by that between the corrugated roll and apasting roll or that between rolls included in a pasting unit.Concerning about a glue amount applied to a single-face web in the gluemachine, the particular control factors are exemplified by a gap amountbetween a pasting roll disposed along a travel path of the single-faceweb and the travel path. In relation to a heat amount applied to adouble-face web in the double facer, the particular control factors arepressure applied by a press unit to the double-face web toward hotplatesarranged along the travel path of the double-face web, a vapor pressureapplied to the hotplates, a travel speed of the double-face web on thehotplates.

If the corrugated-board fabrication machine further includes a bottomliner lubrication unit to lubricate a bottom liner before or aftergluing a single-face web to a top liner in the double facer, and a topliner lubrication unit to lubricate a top liner before or after thegluing, a lubrication amount to a bottom liner from the bottom linerlubrication unit and a lubrication amount to a top liner from the topliner lubrication unit may be added to the particular control factors.The lubrication manner is exemplified by spraying water onto a web froma shower unit or by applying water onto the web with a water-applyingroll.

The control means preferentially controls, if the optimumrunning-condition information retaining means retains the optimumrunning-condition information corresponding to a current productionstate, a particular control factor so as to attain the optimum runningcondition. It is satisfactory that the control means controls at leastone of the particular control factors.

With this configuration, if the current production state is identical toa former production state, particular control factors are automaticallycontrolled so as to be in the optimum running state corresponding to theformer production state. The quality of corrugated board sheets isthereby ensured without depending on the experience of an operator andthe kno-how.

Preferably, the system further comprises warp status informationobtaining means and control factor selecting means.

The warp status information obtaining means obtains informationconcerning warp of a corrugated board sheet fabricated by thecorrugated-board fabrication machine.

The warp status information obtaining means includes selection means forreceiving the operator's selection for an arbitrary one from a pluralityof candidates indicating status of warp. The warp status informationobtains the selected candidate as information concerning the warp statusof the corrugated board sheet.

Otherwise, the warp status information obtaining means may includeimaging means for imaging a corrugated board sheet fabricated by thecorrugated-board fabrication machine and detection means for detectingthe warp of the corrugated board sheet on the basis of image dataobtained by the imaging means so that the warp status informationobtaining means obtains the data detected by the detection means asinformation concerning status of the warp.

Alternatively, the warp status information obtaining means comprisesvariation amount detecting means for detecting a vertical variationamount of a corrugated board sheet and detection means for detectingwarp of the corrugated board sheet on the basis of information of thevertical variation amount obtained by the variation amount detectingmeans so that the warp status information obtaining means obtainsdetected by the detection means may be regarded as informationconcerning status of the warp of the corrugated board sheet.

Further alternatively, the warp status information obtaining meansincludes moisture content measuring means for measuring moisturecontents of a bottom liner and a top liner or parameters correlatingwith the moisture contents and detection means for detecting the warp ofthe corrugated board sheet on the basis of data obtained by the moisturecontent measuring means, and the warp status information obtaining meansregards data obtained by the detection means as the warp statusinformation. One or more temperature sensors or moisture sensors serveas the moisture content measuring means, for example.

The control factor selecting means selects at least one from a pluralityof particular control factors affecting moisture content of a bottomliner or a top liner in accordance with warp status of the corrugatedboard sheet and an influence of each of the plurality of particularcontrol factors on warp of the corrugated board sheet.

In this case, the control variable calculating means calculates acontrol variable of the selected particular control factor based on thewarp status information of the corrugated board sheet and the runningstate information of the corrugated-board fabrication machine. If anyoptimum running-condition information retained in the optimumrunning-condition information retaining means does not correspond to thecurrent production state, the control means controls the selectedparticular control factor using the controls variable calculated by thecontrol variable calculating means.

As detailed described above, each time a corrugated board sheetfabricated in the system for fabricating a corrugated board sheet of thepresent invention satisfies the predetermined quality, a portion of therunning state of particular control factors, which portion is associatedwith a particular control factor that affects the predetermined quality,is stored in the optimum running-condition information retaining meansso that the portion of the running-state information serves as optimumrunning-condition information concerning an optimum running condition ofthe corrugated-board fabrication machine corresponding to the concurrentproduction state. Since, if the optimum running condition correspondingto the current production state is retained in the optimumrunning-condition information retaining means, the particular controlfactor is automatically controlled so as to be in the optimum runningcondition, it is advantageously possible to fabricate a corrugated boardsheet which satisfies the predetermined quality without depending on theexperience of an operator and the know-how.

(3)

The third object of the present invention is quantitative detection oftravel-direction warp and twist warp of a corrugated board sheet.

In order to attain the above third object, a warp detection apparatus,of the present invention, comprising: variation amount detecting meansfor detecting an amount of vertical variation of the corrugated boardsheet fabricated in a corrugated-board fabrication machine in adirection of travel of the corrugated board sheet; and warp amountcalculating means for calculating an amount of warp in the direction oftravel on the basis of the amount of vertical variation detected by thevariation amount detecting means.

Otherwise, a warp detection apparatus, of the present inventioncomprising: variation amount detecting means for detecting amounts ofvertical variation at the four corners of the corrugated board sheetfabricated in a corrugated-board fabrication machine; and warp amountcalculating means for calculating an amount of twist warp of thecorrugated board sheet on the basis of the amounts of vertical variationdetected by the variation amount detecting means.

Otherwise, in the present invention, a warp detection apparatus,comprising: variation amount detecting means for detecting amounts ofvertical variation at the four corners and at the centers of the foursides of the corrugated board sheet fabricated in a corrugated-boardfabrication machine; and warp amount calculating means for calculatingamounts of warp in a direction across a width, warp in a direction oftravel, and twist warp of the corrugated board sheet on the basis of theamounts of vertical variation detected by the variation amount detectingmeans.

In these warp detection apparatuses, the variation amount detectingmeans may include imaging means and image analysis means to analyzevertical variation amounts on the basis of image data from the imagingmeans. In this case, the imaging means has one or more CCD cameras, forexample.

Still further, the present invention may be featured by a method fordetecting a warp amount of a corrugated board sheet fabricated in acorrugated-board fabrication machine comprising the steps of: detectingamount of vertical variation of the corrugated board sheet in adirection of travel of the corrugated board sheet; and calculatingamount of the warp in the direction of travel on the basis of the amountof vertical variation detected in the detecting step.

Still further, the present invention is featured by another method fordetecting warp amount of a corrugated board sheet fabricated in acorrugated-board fabrication machine comprising the steps of: detectingamounts of vertical variation at the four corners of the corrugatedboard sheet; and calculating amount of twist warp of the corrugatedboard sheet on the basis of the amounts of vertical variation detectedin the detecting step.

Still further, the present invention is featured by another method fordetecting a warp amount of a corrugated board sheet fabricated in acorrugated-board fabrication machine comprising the steps of: detectingamounts of vertical variation at the four corners and at the centers ofthe four sides of the corrugated board sheet; and calculating amounts ofwarp in a direction across a width, warp in a direction of travel, andtwist warp of the corrugated board sheet on the basis of the amounts ofvertical variation detected in the detecting step.

With this configuration, it is possible for the present invention toquantitatively obtain an amount of each type of warp, particularlytravel-direction warp and twist warp, so that, on the basis of thedetection result, an accurate status of the warp can effectively bedetected.

The above detection of warp status enables warp correction to beautomatically executed whereby an operator does not have to visuallycheck the warp status and burden on the operator can be greatly reduced.

(4)

The fourth object of the present invention is to inhibit width-directionS-shape warp of a corrugated board sheet, while concurrently maintainingan optimum tension of the corrugated board sheet.

To attain the above object, the present invention has the followingconfiguration (a) or (b).

(a)

In order to accomplish the above fourth object, a preheater, included ina corrugated-board fabrication machine of the present invention, forheating a web, which is to be made into a corrugated board sheet bygluing the web to a web in a corrugated-board fabrication process, priorto the gluing using heating means including a plurality of heating unitsarranged in a direction across a width of the first web and beingoperable to adjust an amount of heat to be applied to the first web byeach of the plurality of heating units.

As a preferable feature, the corrugated-board fabrication machine mayinclude moisture content measuring means for measuring moisture contentof the first web or a parameter correlating with the moisture contentalong the width direction of the first sheet and control means forindividually controlling the plurality of heating units arranged in thewidth direction of the first sheet based on the detection resultobtained by the moisture content measuring means such that the moisturecontent of the first web becomes a predetermined value.

Preferably, the heating means, for example, takes the form of a heatingroll that heats a web wrapped around the roll. In this case, the heatingmeans further includes wrap amount adjusting means, and, first of all,controls a wrap amount of a web using the wrap amount adjusting means toa heat amount applied to the web across the entire width thereof basedon the measurement result obtained by the moisture content measuringmeans such that the moisture contents of the web become a predeterminedvalue. Then the control means controls the individual heating unitsarranged along the web width direction so as to adjust a heat amountapplied to the web in accordance with the width direction.

With this structure, the preheater of the present invention can controlheat amounts of individual heating units arranged along the web widthdirection so that the heat amount applied to a web can be adjusted inaccordance with the web width direction, maintaining the optimum tensionof the web. As a result of the adjustment, variation in the moisturecontent along the width direction of a web can be inhibited wherebywidth-direction S-shape warp can also be inhibited.

Further, when the moisture content measuring means is arranged asdescribed above and the control means controls a heat amount applied byeach individual heating unit on the basis of the measurement resultobtained by the moisture content measuring means in such a manner thatthe moisture content of the web becomes the predetermined value, it ispossible to automatically inhibit width-direction S-shape warp.

Also as described above, when the control means, first of all, controlsa warp amount of a web together with the warp amount adjusting means inorder to adjust a heat amount applied to the web across the entire widthof the web such that the moisture content of the web becomes apredetermined value and then controls heat amounts applied by theindividual heating units such that a heat amount applied to the web isadjusted in accordance with the width direction, temperature control forthe web can be carried out effectively.

(b)

To accomplish the fourth object, the invention's double facer, disposedin a corrugated-board fabrication machine, for fabricating a double-facecorrugated board sheet by gluing a single-face web to a top liner whilethe single-face web and the top liner are sliding on a hotplate, whereinthe hot plate includes a plurality of heating chambers arranged in adirection across a width of the single-face web and is operable toadjust an amount of heat to be applied to the single-face web and thetop liner by each of the plurality of heating chambers.

Preferably in this case, the double facer further includes moisturecontent measuring means for measuring a moisture content or a parametercorrelating with the moisture content of at least one of the single-faceweb and the top liner and control means for controlling the heat amountapplied to each individual heating chamber arranged along the widthdirection of the web and the liner on the basis of the measurementresult obtained by the moisture content measuring means such that themoisture contents of the single-face web and the top liner becomepredetermined values.

For example, a press unit is disposed in order to press the single-faceweb and the top liner toward the hotplate. And, on the basis of themeasurement result by the moisture content measuring means, such thatthe moisture contents of the single-face web and the top liner becomethe predetermined values, the control means controls, first of all,pressing force of the press unit to adjust a heat amount applied to theentire width of the single-face web and the top liner, and then controlsa heat amount applied by each of the heating chambers arranged in theweb width direction so that a heat amount, applied to the single-faceweb and the top liner is controlled in accordance with the widthdirection.

The hotplates may be disposed on the single-face-web side and thetop-liner side so as to be interposed by the travel path of thesingle-face web and the top liner.

With this configuration, control over a heat amount by each of theheating chambers along the web width direction adjusts the heat amountapplied in the web-width direction so that variation in moisture contentof the single-face web and the top liner can be diminished andwith-direction S-shape warp can be advantageously inhibited.

Since the moisture content measuring means is installed and the controlmeans controls heat amounts of individual heating chambers based on themeasurement result of the moisture content measurement means such thatthe moisture contents of a single-face web and a top liner becomepredetermined values, it is possible to automatically inhibitwidth-direction S-shape warp.

Further, the press unit is disposed in order to press a single-face weband a top liner toward the hotplate and the control means controls,first of all, press force of the press unit to adjust a heat amountapplied to the single-face web and the top liner along the entire widththereof such that the moisture contents of the single-face web and thetop liner become the predetermined values, and then controls a heatamount applied by each of the heating chambers arranged in the web widthdirection so that a heat amount applied to the single-face web and thetop liner is adjusted in accordance with the width direction. With thisconfiguration, the temperatures of the single-face web and the top linercan be effectively controlled.

Still further, hotplates disposed on the single-face-web side and thetop-liner side can execute sensitive temperature control over asingle-face web and a top liner.

(5)

The fifth object of the present invention is to provide a counter forcounting the number of corrugated board sheets fabricated, as finalproducts to be shipped, in a corrugated-board fabrication machine.

To attain the fifth object, there is provided a counter for counting thenumber of corrugated board sheets fabricated in a corrugated-boardfabrication machine, comprising: imaging means for imaging edges of thecorrugated board sheets stacked in a stack section which edges are alonga direction of the width of the corrugated board sheets; and imageanalysis means for counting the number of corrugated board sheets byanalyzing image data obtained by the imaging means and recognizing eachof the corrugated board sheets on the basis of a specification for aflute of medium webs of the corrugated board sheets.

With this configuration, the number of corrugated board sheets stackedin the stack section is counted by analyzing image data obtained by theimaging means on the basis of the flute specification for a medium web,it is possible to count the accurate number of corrugated board sheetsthat are to be shipped as final products.

Further, there is provided a counter for counting the number ofcorrugated board sheets fabricated in a corrugated-board fabricationmachine, comprising: height measuring means for measuring a height ofthe corrugated board sheets stacked in a stack section; and numbercalculating means for calculating the number of corrugated board sheetson the basis of the height measured by the height measuring means and athickness per corrugated board sheet.

With this configuration, the number of corrugated board sheets stackedin the stack section is calculated based on the height of the corrugatedboard sheets stacked in the stacking section measured by the heightmeasuring means and a thickness per corrugated board sheet, it ispossible to accurately count the number of corrugated board sheets thatcan be shipped as final products.

Still further, there is provided a counter for counting the number ofcorrugated board sheets fabricated in a corrugated-board fabricationmachine, comprising: height measuring means for measuring a height ofthe corrugated board sheets stacked in a stack section; and numbercalculating means for counting the number of corrugated board sheets byincreasing the number each time the height measured by the heightmeasuring means increases as compared to the previous heightmeasurement.

With such a configuration, the number of corrugated board sheets arecounted in increments of one each time the height of corrugated boardsheets stacked in the stacking section increases. Even if thespecifications of corrugated board sheets are changed, it isadvantageously possible to omit an operation of inputting a flutespecification and/or a sheet thickness in addition to the foregoingadvantages.

Each of the above counters may preferably include sheet number printingmeans for printing the counted number of corrugated board sheets.

Advantageously, with this sheet number printing means for printing thecounted number of corrugated board sheets, production management forcorrugated board sheets can be carried out with ease.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically showing a system for correctingpossible warp of a corrugated board sheet according to a firstembodiment of the present invention;

FIG. 2 is a diagram schematically showing a configuration of a bottomliner preheater, a single facer and a medium web preheater of acorrugated-board fabrication machine;

FIG. 3 is a diagram schematically showing a configuration of asingle-face web preheater, a top liner preheater, a glue machine, and apart of a double facer of the corrugated-board fabrication machine;

FIG. 4 is a diagram schematically showing a configuration of the doublefacer of the corrugated-board fabrication machine;

FIG. 5 is a table showing an acquaintance database according to thefirst embodiment of the present invention;

FIG. 6 is a flow diagram illustrating a succession of procedural stepsof correcting warp according to the first embodiment of the presentinvention;

FIG. 7 is a table showing an acquaintance database according to a secondembodiment of the present invention;

FIG. 8 is a table showing an acquaintance database according to a thirdembodiment of the present invention;

FIG. 9 is a table showing an acquaintance database according to a fourthembodiment of the present invention;

FIG. 10 is a table showing an acquaintance database according to a fifthembodiment of the present invention;

FIG. 11 is a block diagram schematically illustrating a system forcorrecting possible warp of a corrugated board sheet according to asixth embodiment of the present invention;

FIG. 12 is a diagram schematically showing a configuration of a stackerof the corrugated-board fabrication machine and warp status informationobtaining means according to a sixth embodiment of the presentinvention;

FIG. 13 a is a perspective diagram schematically showing the warp statusinformation obtaining means according to the sixth embodiment, imaging acorrugated board sheet using a CCD camera (imaging means);

FIG. 13 b is a schematic diagram showing the warp status informationobtaining means according to the sixth embodiment to explain a manner ofwarp detection;

FIG. 14 a is a diagram schematically showing a side view of warp statusinformation obtaining means according to a seventh embodiment of thepresent invention;

FIG. 14 b is a diagram showing the warp status information obtainingmeans, enlarging the X1 part in FIG. 14 a;

FIG. 15 a is a diagram schematically showing a side view of warp statusinformation obtaining means according to an eighth embodiment of thepresent invention;

FIG. 15 b is a diagram showing the warp status information obtainingmeans, enlarging the X2 part in FIG. 15 a;

FIG. 15 c is a schematic diagram showing the warp status informationobtaining means according to the eighth embodiment to explain a mannerof warp detection;

FIG. 16 is a diagram schematically showing a modification of the warpstatus information obtaining means according to the eighth embodiment;

FIG. 17 is a block diagram schematically showing a system for correctingpossible warp of a corrugated board sheet according to a ninthembodiment of the present invention;

FIG. 18 is a diagram schematically showing a configuration of a powderbrake (a brake device) for a single-face web according to the ninthembodiment;

FIG. 19 is a diagram schematically showing a suction brake (a brakedevice) for a single-face web according to the ninth embodiment;

FIG. 20 is a table showing an acquaintance database according to a tenthembodiment of the present invention;

FIG. 21 is a block diagram schematically showing a system for correctingpossible warp of a corrugated board sheet according to the tenthembodiment;

FIG. 22 is a diagram schematically showing a wrap roll for a single-faceweb according to the tenth embodiment;

FIG. 23 is a table showing an acquaintance database according to thetenth embodiment;

FIG. 24 is a block diagram schematically showing a system for correctingpossible warp of a corrugated board sheet according to an eleventhembodiment of the present invention;

FIG. 25 is a diagram schematically showing corrugated-board warp statusobtaining means according to the eleventh embodiment;

FIG. 26 is a diagram to explain a manner of obtaining warp status of acorrugated board sheet according to the eleventh embodiment;

FIG. 27 is a diagram schematically showing corrugated-board warp statusobtaining means according to a twelfth embodiment of the presentinvention;

FIG. 28 is a schematic diagram showing a manner of obtaining a warpstatus of a corrugated board sheet according to the twelfth embodiment;

FIG. 29 is a block schematic diagram showing a modification of themanner of obtaining a warp status of a corrugated board sheet accordingto the twelfth embodiment;

FIG. 30 is a block diagram schematically showing a system for correctingpossible warp of a corrugated board sheet according to a thirteenthembodiment of the present invention;

FIG. 31 is a schematic diagram showing a configuration of a double faceraccording to the thirteenth embodiment;

FIG. 32 is a plain view showing a configuration of a press roll in thedouble facer according to the thirteenth embodiment;

FIG. 33 a is a perspective view schematically explaining a manner ofcorrecting twist warp and showing types of twist warp according to thethirteenth embodiment;

FIG. 33 b is a perspective view schematically explaining a manner ofcorrecting twist warp and showing types of twist warp according to thethirteenth embodiment;

FIG. 33 c is a plain view schematically explaining a manner ofcorrecting twist warp and showing a press roll according to thethirteenth embodiment;

FIG. 33 d is a plain view schematically explaining a manner ofcorrecting twist warp and showing a press roll according to thethirteenth embodiment;

FIG. 34 is a table showing an acquaintance database according to thethirteenth embodiment;

FIG. 35 is a flow diagram illustrating a succession of procedural stepsfor correcting warp according to the thirteenth embodiment;

FIG. 36 is a front view (seen from web-travel direction) schematicallyshowing a press roll of a double facer according to a fourteenthembodiment of the present invention;

FIG. 37 is a table showing an acquaintance database according to thefourteenth embodiment;

FIG. 38 is a table showing an acquaintance database according to afifteenth embodiment of the present invention;

FIG. 39 is a plain view schematically showing a suction brake for asingle-face web according to the fifteenth embodiment;

FIG. 40 is a table showing an acquaintance database according to asixteenth embodiment of the present invention;

FIG. 41 is a block diagram schematically showing a system for correctingpossible warp of a corrugated board sheet according to a seventeenthembodiment of the present invention;

FIG. 42 is a diagram schematically showing corrugated-board warp statusobtaining means according to the seventeenth embodiment;

FIG. 43 a is a perspective diagram showing a manner of obtaining warpstatus information of a corrugated board sheet according to theseventeenth embodiment when imaging a corrugated board sheet using a CCDcamera (imaging means);

FIG. 43 b is a front view schematically showing a warped corrugatedboard sheet to explain a manner of obtaining a warp status of thecorrugated board sheet;

FIG. 44 is a schematic diagram showing a corrugated-board warp statusobtaining means according to an eighteenth embodiment;

FIG. 45 is a schematic diagram illustrating a manner of obtaining a warpstatus of a corrugated board sheet according to the eighteenthembodiment;

FIG. 46 is a block diagram schematically illustrating a system forcorrecting possible warp of a corrugated board sheet according to anineteenth embodiment of the present invention;

FIG. 47 is a schematic diagram illustrating a single-face web preheater,a top liner preheater, a glue machine, and a part of a double facerincluded in a corrugated-board fabrication machine;

FIG. 48 is a table showing an acquaintance database of the nineteenthembodiment;

FIG. 49 is a table illustrating a configuration of a warp statusjudgment section of the nineteenth embodiment;

FIG. 50 is a flow diagram illustrating a succession of procedural stepsof warp correction according to the nineteenth embodiment;

FIG. 51 is a table showing an acquaintance database according to atwentieth embodiment;

FIG. 52 is a table showing an acquaintance database according to atwenty-first embodiment;

FIG. 53 is a table showing an acquaintance database according to atwenty-second embodiment;

FIG. 54 is a table showing an acquaintance database according to atwenty-third embodiment;

FIG. 55 is a block diagram schematically illustrating a system forcorrecting possible warp of a corrugated board sheet according to atwenty-fourth embodiment of the present invention;

FIG. 56 is a table showing a configuration of a warp status judgmentsection according to the twenty-fourth embodiment;

FIG. 57 is a block diagram schematically illustrating a system forcorrecting possible warp of a corrugated board sheet according to atwenty-fifth embodiment of the present invention;

FIG. 58 is a block diagram schematically showing a modification of asystem for correcting possible warp of a corrugated board sheet of thetwenty-fifth embodiment;

FIG. 59 is a block diagram schematically illustrating a corrugated-boardfabrication system according to a twenty-sixth embodiment of the presentinvention;

FIG. 60 is a block diagram schematically illustrating a corrugated-boardfabrication system according to a twenty-seventh embodiment of thepresent invention;

FIG. 61 is a table showing an acquaintance database according to thetwenty-seventh embodiment;

FIG. 62 is a flow diagram illustrating a procedural steps of warpcorrection of the twenty-seventh embodiment;

FIG. 63 is a block diagram schematically illustrating a corrugated-boardfabrication system according to a twenty-eighth embodiment of thepresent invention;

FIG. 64 is a block diagram schematically illustrating a corrugated-boardfabrication system according to a twenty-ninth embodiment of the presentinvention;

FIG. 65 is a table showing a configuration of a warp status judgmentsection of the twenty-ninth embodiment;

FIG. 66 is a block diagram schematically illustrating a corrugated-boardwarp status detection unit and a corrugated board sheet fabricationmachine according to the thirtieth embodiment of the present invention;

FIG. 67 is a perspective view schematically showing a manner ofdetecting a warp status of the thirtieth embodiment;

FIG. 68 is a diagram schematically illustrating a configuration of amodification of variation amount detecting means of the thirtiethembodiment;

FIG. 69 a is a diagram schematically illustrating a configuration of amodification of variation amount detecting means of the thirtiethembodiment;

FIG. 69 b is a diagram schematically illustrating a configuration of amodification of variation amount detecting means of the thirtiethembodiment;

FIG. 70 a is a sectional front view schematically illustrating the mainpart (a heating roll) of a bottom liner preheater according to athirty-first embodiment of the present invention;

FIG. 70 b is a schematic diagram showing the main part (a heating roll)of the bottom liner preheater of the thirty-first embodiment;

FIG. 71 is a block diagram schematically illustrating a corrugated-boardfabrication machine according to the thirty-first embodiment;

FIG. 72 is a schematic diagram showing the bottom liner preheater, amedium web preheater and a single facer of the thirty-first embodiment;

FIG. 73 is a diagram schematically showing a configuration of asingle-face web preheater, a top-liner preheater, a glue machine and apart of a double facer of the thirty-first embodiment;

FIG. 74 is a sectional front view schematically showing the main part (aheating roll) of a modification of the bottom liner preheater of thethirty-first embodiment;

FIG. 75 a is a sectional front view schematically showing the main part(a heating roll) of a modification of a bottom liner preheater accordingto thirty-second embodiment of the present embodiment;

FIG. 75 b is a diagram showing a configuration of the main part (aheating roll) of a bottom liner preheater of the thirty-secondembodiment;

FIG. 76 a is a sectional front view schematically showing the main part(a hotplate) of a double facer according to a thirty-third embodiment ofthe present invention;

FIG. 76 b is a sectional view schematically showing the main part (ahotplate) of the double facer according to the thirty-third embodiment;

FIG. 77 is a schematic diagram illustrating the entire part of thedouble facer of the thirty-third embodiment;

FIG. 78 is a schematic diagram illustrating a configuration of acorrugated-board fabrication machine of the thirty-third embodiment;

FIG. 79 is a sectional view schematically showing a configuration of themain part of a double facer according to a thirty-fourth embodiment ofthe present invention;

FIG. 80 is a sectional front view, corresponding to FIG. 76 a,illustrating a configuration of the main part of a double faceraccording to a thirty-fifth embodiment of the present invention;

FIG. 81 is a sectional front view schematically illustrating aconfiguration of the main part of a double facer according to anotherembodiment of the present invention;

FIG. 82 is a schematic diagram illustrating a corrugated-boardfabrication system according to a thirty-sixth embodiment of the presentinvention;

FIG. 83 is a schematic diagram showing a corrugated-board sheet counterthat is an enlargement of the Y part of FIG. 15 a according to thethirty-sixth embodiment;

FIG. 84 is a schematic diagram, corresponding to FIG. 83, showing acorrugated-board sheet counter according to a thirty-seventh embodimentof the present invention;

FIG. 85 is a schematic diagram, corresponding to FIG. 83, showing acorrugated-board sheet counter according to a thirty-eighth embodimentof the present invention; and

FIG. 86 is a sectional front view schematically showing a conventionalpreheater (a heating roll).

BEST MODE FOR CARRYING OUT THE INVENTION

(A)

Hereinafter is a description of a system for correcting a possible warpof a corrugated board sheet according to first through eighthembodiments and modifications thereof with reference to FIGS. 1 through16.

(A-1) First Embodiment

FIG. 1 schematically shows a system for correcting possible warpaccording to a first embodiment of the present invention. The system forcorrecting possible warp of the first embodiment includes acorrugated-board fabrication machine 1 and a production managementmachine 2 to manage the corrugated-board fabrication machine 1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by a medium web preheater12 and then glue the medium web 21 to a bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat asingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13, a double facer 16 tofabricate a corrugated board 24 by gluing the single-face web 22 pastedby the glue machine 15 and the top liner 23 heated by the top linerpreheater 14, a slitter scorer 17 to slit and score the corrugated board24 fabricated by the double facer 16, a cut-off device 18 to make afinal product (a corrugated board sheet) 25 by dividing a corrugatedboard 24 scored by the slitter scorer 17 into separated forms, and astacker 19 to sequentially stack corrugated board sheets in order offabrication.

Among elements 10 to 19, an element that affects moisture content of abottom liner 20 and an element that affects moisture content of a topliner 23 are elements associated with (affect) warp of a corrugatedboard 25 in the width direction (cross-machine direction) of acorrugated board sheet 25. Here, the bottom liner preheater 10, thesingle-face web preheater 13, the top liner preheater 14, the singlefacer 11, the glue machine 15 and the double facer 16 correspond to suchelements. Hereinafter, these elements 10, 11, 13-16 will be describedwith reference to FIGS. 2-4. FIG. 2 schematically shows a configurationof the bottom liner preheater 10, the single facer 11, and the mediumweb preheater 12; FIG. 3, the single-face web preheater 13, the topliner preheater 14, a configuration of the glue machine 15 and a part ofthe double facer 16; and FIG. 4, a configuration of the double facer 16.

As shown in FIG. 2, the bottom liner preheater 10 includes bottom linerheating rolls 101A and 101B vertically arranged. Supplying the inside ofthe bottom liner heating rolls 101A and 101B with vapor heats the bottomliner heating rolls 101A and 101B to predetermined temperatures. Abottom liner 20 sequentially guided by guide rolls 105A, 104A, 106 and104B is wrapped around the curved surfaces of the bottom liner heatingrolls 101A and 101B. Therefore the bottom liner 20 is preheated.

Among these guide rolls 105, 104A, 106 and 104B, the guide roll 104A,which is arranged adjacent to the bottom liner heating roll 101A, issupported by the tip of an arm 103A swingably mounted on the axis of thebottom liner heating roll 101A; and the guide roll 104B, which isarranged adjacent to the other bottom liner heating roll 101B, issupported by the tip of an arm 103B swingably mounted on the axis of thebottom liner heating roll 101B. The arms 103A and 103B are respectivelymoved to an arbitrary position within the angle ranges indicated by thearrows in the accompanying drawing by non-illustrated motors. Here, aset of the guide roll 104A, the arm 103A and the non-illustrated motorand a set of the guide roll 104B, the arm 103B and the non-illustratedmotor function as wrap-amount adjusting units 102A and 102B,respectively.

With this configuration, the bottom liner preheater 10 can adjustmoisture content of bottom liner 20, using vapor pressure supplied tothe bottom liner heating rolls 101A and 101B, and wrap amounts (wrapangles) of the bottom liner 20 around bottom liner heating rolls 101Aand 101B by the wrap-amount adjusting units 102A and 102B. Specifically,higher vapor pressure and/or the larger wrapped amount increases heatapplied to a bottom liner 20 from the bottom liner heating rolls 101Aand 101B so that the bottom liner 20 gets drier and thereby the moisturecontent thereof declines.

The single facer 11 includes a press belt 113 wrapped around a belt roll111 and a tension roll 112, an upper roll 114 having a wave-form surfacethat contacts with the press belt 113 in a state of forcing the pressbelr 113, and a lower roll 115 also having a wave-form surface thatengages with the upper roll 114. A bottom liner 20 heated by the bottomliner preheater 10 is wrapped around a liner preheating roll 117 to bepreheated and then guided, together with the press belt 113, to a nipbetween the press roll 113 and the upper roll 114 by the belt roll 111.Meanwhile, a medium web 21 heated by the medium web preheater 12 iswrapped around a medium web preheating roll 118 to be preheated, thencorrugated at the engaging point of the upper roll 114 and the lowerroll 115, and guided to the nip between the press belt 113 and the upperbelt 114 by the upper roll 114.

A pasting unit 116 is disposed close to the upper roll 114. The pastingunit 116 is formed by a glue dam 116 a to store glue 30, a pasting roll116 b to apply the glue to a medium web 21 transferred by the upper belt114, a meter roll 116 c to adjust a glue amount applied to the curvedsurface of the pasting roll 116 b, and a glue sweeping blade 116 d tosweep glue from the meter roll 116 c. Each flute tip of a medium web 21corrugated at the engaging point of the upper roll 114 and the lowerroll 115 is pasted by pasting roll 116 b and the medium web 21 is gluedto the bottom liner 20 at the nip between the press belt 113 and theupper roll 114 whereby a single-face web 22 is fabricated.

With this configuration, the single facer 11 can adjust a moisturecontent of a bottom liner 20 by adjusting a gap amount between thepasting roll 116 b and the upper roll 114 and a gap amount between thepasting roll 116 b and the meter roll 116 c. Concretely, a larger gapamount increases an amount of glue applied to a contact point of mediumweb 21 with bottom liner 20 so that water contained in the glue includesa moisture content of the bottom liner 20. The above gap amounts can beadjusted by a move of the pasting roll 116 b and/or the meter roll 116c.

The medium web preheater 12 is identical in configuration to the bottomliner preheater 11, and includes a medium web heating roll 121 that isheated to a predetermined temperature by vapor being supplied to theinside thereof, and a wrap amount adjusting unit 122 to adjust a wrapamount (wrap angle) of a medium web 21 around the medium web heatingroll 121. The wrap amount adjusting unit 122 includes a guide roll 124around which medium web 21 is to be wrapped, an arm 123 swingablymounted on the axis of the medium web heating roll 121 to support theguide roll 124, and a non-illustrated motor to rotate the arm 123.

As shown in FIG. 3, the single-face web preheater 13 and the top linerpreheater 14 are vertically arranged and are identical in configurationto the above-described bottom liner preheater 11.

The single-face web preheater 13 includes a single-face web heating roll131 and a wrap amount adjusting unit 132. Supplying the inside of thesingle-face web heating roll 131 heats the single-face web heating roll131 to a predetermined temperature. A bottom liner 20 serving one sideof a single-face web 22 guided by guide rolls 135 and 134 is wrappedaround the curved surface of the single-face web heating roll 131 and ispreheated by the single-face web heating roll 131

The wrap amount adjusting unit 132 is formed by the guide roll 134, anarm 133 swingably mounted on the axis of the single-face web heatingroll 131 to support the guide roll 134, and a non-illustrated motor torotate the arm 133. The guide roll 134 is moved to an arbitrary positionwithin the angle range indicated by the arrows in the accompanyingdrawing under control of the motor so that a wrap amount (a wrap angle)of a single-face web 22 around the single-face web heating roll 131 canbe adjusted.

With such a configuration, the single-face web preheater 13 can adjustmoisture content of the bottom liner 20 by adjusting pressure of vaporsupplied to the single-face web heating roll 131 and a wrap amount (awrap angle) of the single-face web 22 around the single-face web heatingroll 131. Specifically, higher vapor pressure or a larger wrap amountincreases heat amount applied to the bottom liner 20 from thesingle-face web heating roll 131 so that the bottom liner 20 gets drierand the moisture content thereof declines.

The top liner preheater 14 includes a top liner heating roll 141 and awrap amount adjusting unit 142. Supplying inside of the top linerheating roll 141 with vapor heats top liner heating roll 141 to apredetermined temperature. A top liner 23 guided by guide rolls 145 and144 is wrapped around the curved surface of the top liner heating roll141, and is preheated by the top liner heating roll 141.

The wrap amount adjusting unit 142 is formed by the guide roll 144, anarm 143 swingably mounted on the axis of the top liner heating roll 141in order to support the guide roll 144, and a non-illustrated motor torotate the arm 143. The guide roll 144 is moved to an arbitrary positionwithin the angle range indicated by the arrows in the accompanyingdrawing under control of the motor so that a wrap amount (a wrap angle)of a top liner 23 around the top liner heating roll 141 can be adjusted.

With such a configuration, the top liner preheater 14 can adjust amoisture content of the top liner 23 by adjusting pressure of vaporsupplied to the top liner heating roll 141 and wrap amount (a wrapangle) of the top liner 23 around the top liner heating roll 141.Specifically, higher vapor pressure or a larger wrap amount increases aheat amount applied to the top liner 23 from the top liner heating roll141 so that the top liner 23 gets drier and the moisture content thereofdeclines.

The glue machine 15 includes a pasting unit 151 and a pressure bar unit152. A single-face web 22 that has been heated by the single-face webpreheater 13 is preheated by a single-web preheating roll 155 and thenis guided into the inside of the glue machine 15 by guide rolls 153 and154. The pasting unit 151 is disposed on the lower side (themedium-web-21 side) of the travel path of a single-face web 22 betweenthe guide rolls 153 and 154 while the pressure bar unit 152 is disposedon the upper side (the bottom-liner-20 side) of the travel path.

The pasting unit 151 includes a glue dam 151 a to store glue 31, apasting roll 151 b disposed adjacent to the travel path of thesingle-face web 22, and a doctor roll 151 c being in contact with thepasting roll 151 b and rotating in the opposite direction to the pastingroll 151 b. The pressure bar unit 152 is formed by a pressure bar 152 aarranged opposite to the pasting roll 151 b in relation to thesingle-face web 22, and an actuator 152 b to press the pressure bar 152a against the pasting roll 151 b. The single-face web 22 is pressedagainst the pasting roll 151 b by the pressure bar 152 a, and the tip ofeach flute of the medium web 21 is pasted by the pasting roll 151 b whenthe single-face web 22 passes through the space between the pressure bar152 a and the pasting roll 151 b. The single-face web 22, whose mediumweb 21 is pasted, is to be glued to a top liner 23 in the ensuingprocess performed in the double facer 16.

With such a configuration of the glue machine 15, a moisture content oftop liner 23 can be adjusted by a gap amount between the pasting roll151 b and the pressure bar 152 a (i.e., a gap amount of the pasting roll151 b in relation to the travel path of the single-face web 22).Specifically, a larger gap amount increases an amount of glue applied toeach combining point of a medium web 21 with a top liner 23, so thatmoisture contained in the top liner 23 increases, thereby increasingmoisture content of the top liner 23. The actuator 152 b can adjust theabove gap amount by adjusting the position of the pressure bar 152 a.

The single-face web 22 pasted in the glue machine 15 is transferred tothe double facer 16 in which the ensuing step is to be performed. Thetop liner 23 heated in the top liner preheater 14 is also transferred tothe double facer 16 through inside of the glue machine 15. During thetransfer, the top liner 23 is guided and preheated by a liner preheatingroll 156, which is arranged in the glue machine 15.

At the entrance of the double facer 16, a first shower unit (a bottomliner lubrication unit) 161A is disposed on the bottom-liner-20 sidealongside a travel path of the single-face web 22; and a second showerunit (a top line lubrication unit) 161B is disposed alongside a travelpath of a top liner 23. These shower units 161A and 161B arerespectively used to adjust moisture contents of a bottom liner 20 and atop liner 23, respectively; the shower unit 161A sprays water over abottom liner 20 and the shower unit 161B sprays water over a top liner23. The moisture content of the bottom liner 20 increases in accordancewith an amount of water sprayed from the shower unit 161A, and themoisture content of the top liner 23 increases in accordance with anamount of water sprayed from the shower unit 161B. These shower units161A and 161B are controlled independently of each other.

The double facer 16 is, as shown in FIG. 4, divided into an upstreamheating section 16A and a downstream cooling section 16B which sectionslie along the travel path of bottom liner 20 and top liner 23. In theheating section 16A, a plurality of hotplates 162 are arranged and topliner 23 passes along upper faces of hotplates 162. Vapor supplied tothe inside of each hot plate 162 heats the hotplate 162 to apredetermined temperature.

On the hotplates 162, a loop-shape press belt 163 interposed by thetravel path runs in synchronization with a single-face web 22 and a topliner 23. A plurality of pressure units 164 are disposed in the loopformed by the press belt 163 so as to be opposite to the hotplates 162.Each of the pressure units 164 is formed by a pressure bar 164 a incontact with the back of the press belt 163 and an actuator 164 b topress the pressure bar 164 a against the hotplate 162.

A single-face web 22 pasted in the glue machine 15 is introduced into aspace between the press belt 163 and the hotplates 162 so as to be incontact with the press belt 163 while a top liner 23 heated by the topliner preheater 14 is further preheated by the liner entrance preheatingroll 165 and then introduced into the space between the press belt 163and the hotplates so as to be in contact with the hotplates 162. Afterbeing introduced into the space between the press belt 163 and thehotplates 162, the single-face web 22 and the top liner 23 pile up toform one body and are transferred to the cooling section 16B. While thesingle-face web 22 and the top liner 23 are transferred, the single-faceweb 22 and the top liner 23 are pressed by the pressure unit 164 withthe press belt 163 interposed and are heated from the top-liner-23 sidewhereupon the single-face web 22 and the top liner 23 are glued togetherto form a double-face web 24. The overall width or the edge of thedouble-face web 24 is cut by a rotary shear 166 installed at the exit ofthe cooling section 16B and then the double-face web 24 is transferredto the slitter scorer 17 at which the ensuing step is to be performed.

With this configuration of the double facer 16, a moisture content of atop liner 23 can be adjusted by vapor pressure supplied to the hotplates162 and pressures applied by pressure units 164. Specifically, highervapor pressures or higher pressures increase heat amount transferred tothe top liner 23 from the hotplates 162, so that the top liner 23 getsdrier and has a low moisture content. A passing rate of a single-faceweb 22 and a top liner 23 in the double facer also adjusts moisturecontent of the top liner 23. A lower rate makes the top liner 23 drierand thereby lowers the moisture content thereof because the top liner 23is in contact with the hotplates 162 for a longer time.

The production management machine 2 corrects width-direction warp of acorrugated board sheet 25 by appropriately controlling these elements10, 11, and 13-16. Focusing on a function for correcting warp ofcorrugated-board-25, the production management machine 2, as shown inFIG. 1, comprises the acquaintance database 3, the control variablecalculating section 4, the process controller 5 and the warp statusinputting section 6.

The acquaintance database 3 retains setting values of control variables(adjustment variations from the current values) associated with one ormore particular control factors that affect the possible warp of acorrugated board sheet 25 which particular control factors are amongcontrol factors used to control the corrugated-board fabrication machine1, or formulae used to determine the control variables that correlatewith warp status (warp direction, warp extent) of the corrugated boardsheet 25. Here, the particular control factors are control factors thataffect moisture contents of bottom liner 20 or top liner 23, and moreparticularly are wrap amounts of the bottom liner 20 around theabove-described bottom liner heating rolls 101A and 101B and a wrapamount of the top liner 23 around the top liner heating roll 141.

For example, when a corrugated board sheet 25 has upward warp in thewidth direction (has the convex surface toward a top liner 23), asetting value or a formula of each control variable is defined in orderto increase a moisture content of the top liner 23 and/or decrease amoisture content of the bottom liner 20. Conversely, when a corrugatedboard sheet 25 has downward warp in the width direction (has a convexsurface toward the bottom liner 20), a setting value or a formula ofeach control variable is defined in order to increase moisture contentof the bottom liner 20 and/or decrease moisture content of the top liner23.

A setting value or a formula of each control variable is defined inaccordance with a predetermined priority order, which is a priorityorder for outputs. For example, when the extent of warp is small, onlycontrol variables with higher priorities are output; and when the extentof warp is increasing, other control variables are additionally outputin accordance with the priority order. A control factor that has greatereffect on warp, i.e., a control factor that contributes more to warpcorrection, gets a higher priority.

The table in FIG. 5 shows the configuration of the acquaintance database3 according to the first embodiment. In the illustrated example, sixwarp status types of large upward warp, medium upward warp, small upwardwarp, large downward warp, medium downward warp and small downward warpare set corresponding to the number of push buttons that is to bedescribed later. For each of the warp state types, control variablesthat are to be output are defined in accordance with a priority order.In the first embodiment, control factors (particular control factors)that are set are a wrap amount around the single-face web preheater (awrap amount of a single-face web 22 around the single-web heating roll131), a wrap amount around a top liner preheater (a wrap amount of a topliner 23 around the top liner heating roll 141) and a wrap amount arounda bottom liner preheater (a wrap amount of a bottom liner 20 around thebottom liner heating roll 101); the wrap amounts around the single-faceweb preheater and around the top liner preheater are given the firstpriority in the priority order and the wrap amount around the bottomliner preheater is given the third priority.

In FIG. 5, a control factor with a circle (∘) or a double circle (⊚) isan output when a corrugated board sheet is in a corresponding warpstatus. A circle and a double circle represent amounts of controlvariable (variations from current values) and a double circle representsa larger control variable than a circle of the same control factor.Accordingly, in this embodiment, if a corrugated board sheet 25 hassmall upward warp for example, only the wrap amounts around thesingle-face web preheater and around the top liner preheater areadjusted; if corrugated board sheet 25 has medium upward warp, only theamounts around the single-face web preheater and around the top linerpreheater are similarly adjusted and the amounts of the adjustmentvariables thereof are increased; and if a corrugated board sheet 25 haslarge upward warp, a wrap amount around the bottom liner preheater isadditionally adjusted. Specific setting values and formulae to derivethe setting values are of individual control factors defined byexperiments and simulations.

In this embodiment, a warp status of a corrugated board sheet 25 ismanually input to the warp status inputting section (warp statusinformation obtaining means) 6 by an operator. The warp status inputtingsection 6 includes six push buttons 61 (large upward warp), 62 (mediumupward warp), 63 (small upward warp), 65 (large downward warp), 66(medium downward warp) and 67 (small downward warp), each of whichassociates with a warp status classified in the acquaintance database 3,and a reset button 64. An operator depressing a corresponding buttoninputs a selection signal to the control variable calculating section 4.Warp status of a corrugated board sheet 25 is determined by an operatoras a result of visual observation of the corrugated board sheet 25stacked in the stacker 19.

The control variable calculating section 4 retrieves and reads a settingvariable or a formula to deriver the variable of each correspondingcontrol factor from the acquaintance database 3 on the basis of theselection signal received from the warp status inputting section 6, andcalculates each control variable associated with a machine state (arunning state) of the corrugated-board fabrication machine 1. In theillustrated embodiment, the control variable calculating section 4 andthe acquaintance database 3 serve as the control factor selecting meansand the control variable calculating means according to the presentinvention.

A machine state represents the current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of a web), a wrapamount of a web around each of the heating rolls 101A, 101B, 131 and141, a vapor pressure applied to each of the heating rolls 101A, 101B,131 and 141, gap amounts between the rolls 116 b and 114 and between therolls 116 b and 116 c in the single facer 11, a gap amount between thepasting roll 151 b and the pressure bar 152 a in the glue machine 15,pressure applied by the pressure units 164 and vapor pressure applied tothe hotplates 162 in the double facer 16, and spray amounts of theshower units 161A and 161B. These values of the machine state are inputfrom the process controller 5, which is to be described later.

When the reset button 64 is selected in the warp status inputtingsection 6, the control variable calculating section 4 instructs theprocess controller 5 to return all the control factors to their originalvalues (values determined by matrix control based on production stateinformation such as base-board composition, basis weight of the baseboard, the width of corrugated board sheet, flute and the like).

The process controller 5 has overall control of each of the elements10-19 that constitute the corrugated-board fabrication machine 1. Theprocess controller 5 usually controls each of the elements 10-19 byperforming matrix control based on production state information.However, when one from the push buttons 61-63 and 65-67 is depressed inthe warp status inputting section 6, the process controller 5 controlseach of control factors (here, one or an arbitrary combination of a wrapamount around the single-web preheater 13, a wrap amount around the topliner preheater 14, and a wrap amount around the bottom liner preheater10) using one or more control variables calculated in the controlvariable calculating section 4. When the reset button 64 is depressed,the process controller 5 controls elements 10, 13, and 14 to return allthe control factors to their original values. The process controller 5always grasps a current machine state of the corrugated-boardfabrication machine 1, and outputs the current machine state to thecontrol variable calculating section 4 periodically or in response to arequest from the control variable calculating section 4. Namely, theprocess controller 5 serves as the control means and the running-stateinformation obtaining means according to the present invention.

The flow diagram in FIG. 6 describes a succession of procedural steps ofcorrecting warp of a corrugated board sheet 25 using the above-describedfunctions of the production management machine 2.

First of all, the production management machine 2 checks a machine stateat step A10 and checks a production state at step A20. In the ensuingstep A30, the production management machine 2 judges whether or not awarp status can be currently input (one from the push button 61-67 canbe depressed). The judgment is made so as not to correct warp whileanother problem arises because warp correction is useless when such aproblem, e.g., a low rate of web travel due to an excessively strongadhesive of glue, arises.

If a warp status can be input at step A30, the production managementmachine 2 judges whether or not a warp status has been actually input atstep A40. If a warp status has been input, the production managementmachine 2 selects one or more control factors (here, one or acombination of a wrap amount around the single-face web preheater, awrap amount around the top liner preheater, and a wrap amount of thebottom liner preheater) in accordance with a priority order of the inputwarp status, i.e., the selected one of the push buttons 61-63 and 65-67.

In succession at step A60, the production management machine 2 refers tothe acquaintance database 3 and calculates one or more control variablesassociated with the machine state obtained in step A10. At this time,production management machine 2 may use the production state informationobtained at step A20 as reference data, for example, in order to changewrap amounts considering base paper composition (thick paper, thinpaper). The production management machine 2 outputs the calculatedcontrol variables to corresponding elements (here, one or a combinationof the single-face web preheater 13, the top liner preheater 14, and thebottom liner preheater 10) at step A70.

According to the system for correcting possible warp of a corrugatedboard sheet of the first embodiment, by an operator visually judging awarp status of a corrugated board sheet 25 fabricated in thecorrugated-board fabrication machine 1 and simply depressing one ofbuttons 61-63 and 65-67 in accordance with the judged warp status, awrap amount around the single-face web preheater, a wrap amount aroundthe top liner preheater and a wrap amount around the bottom linerpreheater, which amounts affect warp of a corrugated board sheet 25, areautomatically adjusted by the production management machine 2. Thereby,it is possible to accurately correct warp of corrugated board sheetswith ease without depending on the experience of an operator and theknow-how.

At that time, since the production management machine 2 successivelyadds selected control factors in accordance with the predeterminedpriority order, considering extent of warp of a corrugated board sheet25, the extent of adjustment for warp correction can be larger inaccordance with the warp extent so that warp correction of corrugatedboard sheet 25 can be accomplished rapidly. In particular in thisembodiment, it is possible to correct warp of a corrugated board sheet25 yet faster by providing a control factor that more largely affectsthe warp with a higher priority.

In the first embodiment, the control factors to correct warp of acorrugated board sheet 25 are a wrap amount around the single-face webpreheater, a wrap amount around the top liner preheater and a wrapamount around the bottom liner preheater. These control factors are onlyone example and a greater number of control factors to be controlled maybe used likewise in the following second through fifth embodiments.

(A-2) Second Embodiment

FIG. 7 shows the configuration of the acquaintance database 3 accordingto the second embodiment of the present invention. The elements exceptthe acquaintance database 3 are identical to those of the firstembodiment, so repetitious description will be omitted here.

In this embodiment, the single facer 11 and the glue machine 15 are alsocontrolled in order to correct warp. An adhesive-gap amount of thesingle facer (a gap amount between the pasting roll 116 b and the upperroll 114 (or a gap amount between the pasting roll 116 b and the meterroll 116 c)) and an adhesive-gap amount of the glue machine (a gapamount between the pasting roll 151 b and the pressure bar 152 a) areset as particular control factors in addition to control factors of thefirst embodiment. In the same manner as the first embodiment, the wrapamounts around the single-face web preheater and around the top linerpreheater are given the first priority in the priority order and thewrap amount around the bottom liner preheater is given the thirdpriority. Meanwhile the adhesive-gap amount of the single facer and theadhesive-gap amount of the glue machine are given the fourth and thefifth priorities, respectively.

Since the system for correcting a possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the first embodiment, it is possible to perform moresensitive control than the first embodiment so that warp of a corrugatedboard sheet 25 can be corrected more accurately.

(A-3) Third Embodiment

FIG. 8 shows the configuration of the acquaintance database 3 accordingto a third embodiment of the present invention. The elements in thisembodiment except the acquaintance database 3 are also identical tothose of the first embodiment, so repetitious description will beomitted here.

In this embodiment, the double facer 16 is also controlled in order tocorrect warp. A pressure applied by the double facer (pressure appliedby the pressure units 164) and a rate of the double facer (a travel rateof a single-face web 22 and the top liner 23 in the double facer 16) areset as particular control factors in addition to control factors of thesecond embodiment. In the same manner as the second embodiment, the wrapamounts around the single-face web preheater and around the top linerpreheater are given the first priority in the priority order; the wrapamount around the bottom liner preheater is given the third priority;the adhesive-gap amount of the single facer is given the fourthpriority; and the adhesive-gap amount of the glue machine is given thefifth priority while the pressure of the double facer and the rate ofthe double facer are given the sixth and the seventh priorities,respectively.

Since the system for correcting a possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the second embodiment, it is possible to perform moresensitive control than the second embodiment so that warp of acorrugated board sheet 25 can be corrected more accurately.

(A-4) Fourth Embodiment

FIG. 9 shows the configuration of the acquaintance database 3 accordingto a fourth embodiment of the present invention. Also in thisembodiment, the elements except the acquaintance database 3 areidentical to those of the first embodiment, so repetitious descriptionwill be omitted here.

In this embodiment, a vapor pressure in the double facer (a pressure ofvapor applied to the hotplates 162) is added as a particular controlfactor to the control factors of the third embodiment. In the samemanner as the second embodiment, the wrap amounts around the single-faceweb preheater and around the top liner preheater are given the firstpriority in the priority order; the wrap amount around the bottom linerpreheater is given the third priority; the adhesive-gap amount of thesingle facer is given the fourth priority; and the adhesive-gap amountof the glue machine is given the fifth priority; and the pressure of thedouble facer is given the sixth priority. Meanwhile the vapor pressurein double facer and the rate of the double facer are given the seventhand the eighth priorities, respectively.

Since the system for correcting a possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the third embodiment, it is possible to perform moresensitive control than the third embodiment so that warp of a corrugatedboard sheet 25 can be corrected more accurately.

(A-5) Fifth Embodiment

FIG. 10 shows the configuration of the acquaintance database 3 accordingto a fifth embodiment of the present invention. The elements except theacquaintance database 3 are also identical to those of the firstembodiment, so repetitious description will be omitted here.

In this embodiment, the shower units 161A and 161B are also controlledin order to correct warp. A spray amount onto the bottom liner side (anamount of spray from the shower unit 161A) and a spray amount onto thetop liner side (an amount of spray from the shower unit 161B) are addedas particular control factors to the control factors of the fourthembodiment. These spray amounts are given the first priority while thewrap amounts around the single-face web preheater and around the topliner preheater are given the second priority in the priority order; thewrap amount around the bottom liner preheater is given the fourthpriority; the adhesive-gap amount of the single facer is given the fifthpriority; and the adhesive-gap amount of the glue machine is given thesixth priority; the pressure of the double facer is given the seventhpriority; the vapor pressure in double facer is given the eighthpriority; and the rate of the double facer is given the ninth priority.

Since the system for correcting possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the fourth embodiment, it is possible to perform moresensitive control than the fourth embodiment so that warp of acorrugated board sheet 25 can be corrected more accurately. The addedspray amounts with high correction capacities can contribute to furtherrapid warp correction.

(A-6) Sixth Embodiment

Next, a sixth embodiment of the present invention will now be describedwith reference to FIGS. 11-13. The sixth embodiment is featured by meansfor obtaining data in relation to a warp status of a corrugated boardsheet 25. The acquaintance database 3 used in this embodiment can be anyof the first to the fifth embodiments.

As shown in FIG. 11, the production management machine 2 of the sixthembodiment includes a warp status judgment section 8 as a substitute forthe warp status inputting section (push buttons) 6 of the firstembodiment. A CCD camera (imaging means) 7 is disposed at the rearmostsection of the corrugated-board fabrication machine 1.

The CCD camera 7 is arranged at a stacking section 192 of the stacker 19as shown in FIG. 12. Corrugated board sheets 25 are formed by being cutby the cut-off device 18, transferred by a plurality of conveyors 191,and then subsequently piled in the stacking section 192. The CCD camera7 images the width-direction side of corrugated board sheets 25 piled inthe stacking section 192 and outputs the image data to the warp statusjudgment section 8.

The warp status judgment section 8 performs image processing on theimage data from the CCD camera 7 and measures the heights of, forexample, three points (both ends and the center) of the top corrugatedboard sheet 25 which points are arranged along the width directionthereof. Then the warp status judgment section 8 judges a wrap direction(upward or downward) along the width direction and a height extent(large, medium or small) on the basis of the variance of the measuredheights. The result of the judgment is sent to the control variablecalculating section 4, which then selects a control factor based on thejudgment result and calculates a control variable of the selectedcontrol factor in accordance with machine state information withreference to the acquaintance database 3.

Here, the judgment of a warp status by the warp status judgment section8 will now be specifically described with reference to FIGS. 13 a and 13b. The CCD camera 7 photographs the width-direction side of a corrugatedboard sheet 25 as shown in FIG. 13 a. The warp status judgment section 8performs image processing (analysis) on image data from the CCD camera 7and calculates vertical variations a, band p of predetermined threepoints (the driving-side corner PA, the operating-side corner PB and theweb center PP) arranged in the width direction with respect to thereference line L0.

The warp status judgment section 8 calculates vertical curl-up amountsA1 and B1 of the corners PB and PP with respect to a flat floor,assuming that a corrugated board sheet 25 is placed on the flat floor,on the basis of the vertical variation a, b and p using the followingformulae (1) and (2). Further, the warp status judgment section 8calculates an amount WF_(CD) of warp in the width direction defined interms of the formula below (3) using the vertical curl-up amounts A1 andB1. The warp direction is determined by positiveness and negativeness ofthe warp amount WF_(CD), and the warp height is determined by thelargeness of the absolute value of the warp amount WF_(CD).$\begin{matrix}{{A\quad 1} = {p - a}} & (1) \\{{B\quad 1} = {p - b}} & (2) \\{{{WF}_{CD}\left( {{A\quad 1},{B\quad 1}} \right)} = {\frac{\left( {{A\quad 1} + {B\quad 1}} \right)}{2} \times \frac{\alpha}{W^{2}}}} & (3)\end{matrix}$

where, W represents the length of the width of a corrugated board sheet25, and α is a constant used to make a warp amount dimentionless.

In the system for correcting possible warp of a corrugated board sheetaccording to this embodiment, warp of a corrugated board sheet 25 isautomatically corrected so that it is further possible to accuratelycorrect warp of corrugated board sheets with ease without depending onexperience of an operator and know-how. In the illustrated example, theusage of the acquaintance database 3 according to the first to the fifthembodiments classified a determined warp extent into large, medium andsmall. It is possible for this system to judge a warp extent moresensitively so that warp of a corrugated board sheet 25 can be correctedmore accurately.

(A-7) Seventh Embodiment

FIGS. 14 a and 14 b show a mounting position of a CCD camera 7 accordingto a seventh embodiment of the present invention. In this embodiment,the configuration other than the mounting position of the CCD camera 7is identical to that of the sixth embodiment, so any repetitiousdescription is omitted here.

In the above sixth embodiment, the CCD camera 7 photographs a corrugatedboard sheet 25 that has been formed by being cut by the cut-off device18 and that has been piled in the stacking section 192. Meanwhile, thepresent embodiment photographs a corrugated board sheet 25 at a conveyer191 arranged upstream of the stacking section 192 as shown in FIGS. 14 aand 14 b. In the illustrated example, the CCD camera 7 is fixed througha frame 71 and a CCD camera mounting member 72 in order to be positionedover the conveyer 191 (i.e., above the travel path of a corrugated boardsheet 25).

Accordingly, the system for correcting a possible warp of a corrugatedboard sheet of this embodiment ensures the same advantages as the sixthembodiment.

(A-8) Eighth Embodiment

This embodiment uses a variation sensor 7A (variation amount detectingmeans) as a substitute for the CCD camera (imaging means) 7 so that awarp status judgment section 8 obtains a warp status of a corrugatedboard sheet based on information obtained by the variation sensor 7Awhile the above-described seventh embodiment obtains a warp status of acorrugated board sheet 25 on the basis of image data obtained by a CCDcamera 7.

Specifically, the variation sensor 7A in the illustrated embodiment isattached a variation sensor mounting member 72 a, and is slidablyattached to a rail 71 a (which is fixed to a Flame 71 and extendshorizontally along the width direction of a corrugated board sheet 25),being interposed by the variation sensor mounting member 72 a, as shownin FIGS. 15 a and 15 b. Further, non-illustrated driving means isinstalled in the variation sensor mounting member 72 a and the variationsensor 7A is driven by the driving means so that the variation sensor 7Ais controlled to be positioned over the points of an operating-side edgePR, a driving-side edge PS and a sheet center PT. As a result, it isthereby possible to obtain vertical variation amounts s, t and r betweenthe lens surface of the variation sensor and each point of PR, PS andPT, as shown in FIG. 15 c.

The warp status judgment section 8 calculates vertical curl-up amountsAl and Cl of corners PR and PS of a corrugated board sheet 25 withrespect to a flat floor using the following formulae (4) and (5), and awidth-direction warp amount WF_(CD) is obtained by the above formula(1).A 1=t−s  (4)B 1=t−r  (5)

The remaining configuration is identical to those of the sixthembodiment, so repetitious description will be omitted here.

Accordingly, the system for correcting a possible warp of a corrugatedboard sheet of this embodiment ensures the same advantages as the sixthand seventh embodiments.

In the illustrated embodiment, movement of a single variation sensor 7Ain the width direction of a corrugated board sheet 25 obtains verticalvariation amounts s-r at the respective points PR-PT. Alternatively, asshown in FIG. 16, three variation sensors 7B, 7C and 7D may be fixed toa frame 71 on the same horizontal level so as to be arranged along thewidth direction of a corrugated board sheet 25 (here, vertically overthe points PR-PT), so that vertical variation amounts s-r can beobtained. A part with reference number 72 b in FIG. 16 represents avariation sensor mounting member.

Further alternatively, measurement of vertical variations by thevariation sensor 7A (or the variation sensors 7B, 7C and 7D) may beperformed at the stacking section 192 in the same manner as the sixthembodiment, instead of over the conveyer 191.

(A-9) Others

The above is the description of the first through the eighth embodimentsof the present invention. But, the present invention should by no meansbe limited to the foregoing first to the eighth embodiments and variousalternations and modifications can be suggested without departing fromthe gist of the present invention.

For example, the above embodiments do not use vapor pressures applied toeach of the heating rolls 101, 131 and 141 as particular controlfactors; alternatively, it is, of course, possible to correct warp of acorrugated board sheet 25 by using these control factors. Further, otherthan the above example, any control factor that affects a moisturecontent of a bottom liner 20 or a top liner 23 can be used as aparticular control factor to correct warp of a corrugated board sheet25. Accordingly, the configurations of the acquaintance databases 3 ofthe first through the fifth embodiments are only examples and can becreated in accordance with particular control factors to be used. Thepriority orders in the acquaintance databases 3 should by no means belimited to the foregoing examples and can be arbitrariy set.

(B)

Hereinafter is a description concerning systems for correcting possiblewarp of a corrugated board sheet according to the ninth through twelfthembodiments and their modifications of the present invention withreference to FIGS. 17-29. Parts and elements identical to thosedescribed in the foregoing embodiments are to be referred to by the samereference numbers.

(B-1) Ninth Embodiment

FIG. 17 schematically shows a system for correcting possible warp of acorrugated board sheet according to the ninth embodiment, which includesa corrugated-board fabrication machine 1 and a production managementmachine 2A to manage the corrugated-board fabrication machine 1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by a medium web preheater12 and then glue the medium web 21 to a bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat asingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13, a double facer 16 tofabricate a double-face web 24 by gluing the single-face web 22 pastedby the glue machine 15 and the top liner 23 heated by the top linerpreheater 14, a slitter scorer 17 to slit and score the double-face web24 fabricated by the double facer 16, a cut-off device 18 to make afinal product (a corrugated board sheet) 25 by dividing a double-faceweb 24 scored by the slitter scorer 17 and subjected to anotherprocedure into separated forms, and a stacker 19 to sequentially stackcorrugated board sheets 25 in order of fabrication.

Webs 20, 21 and 23 are forwarded from base-paper rolls rotatably mountedon mill roll stands M1, M2 and M3, respectively.

Brake devices which provide braking force to traveling single-face web22 and top liner 23 are installed in the corrugated-board fabricationmachine 1 in order to serve as control factors that affect tension onwebs 22 and 23 in the travel direction (the flow direction, the machinedirection), i.e., control factors that adjust travel-direction tensions.For instance, the brake device for a top liner 23 takes the form of amill brake 30 arranged at the mill stand M3 for the top liner 23 and apowder brake 31 for a top liner that provides braking force at a pointbetween the top liner preheater 14 and the double facer 16; and thebrake device for a single-face web 22 takes the form of a suction brake32 for a single-face web that provides the single-face web 22 withbraking force at a point between the single facer 11 and the single-faceweb preheater 13 and a powder brake 33 for a single-face web thatprovides the single-face web 22 with braking force at the entrance ofthe glue machine 15.

These brake devices will now be briefly described.

First of all, the powder brake 33 for a single-face web is illustratedto explain the structures of the powder brakes 31 and 33. The powderbrake 33 for a single-face web, as shown in FIG. 18, includes a brakeroll 33 a and a torque adjusting unit 33 c, which is connected to therotating axis 33 b of the brake roll 33 a, to adjust torque of the brakeroll 33 a. Additionally, guide rolls 33 d are arranged upstream anddownstream of the powder brake 33 for a single-face web, so that asingle-face web 22 travels the space between each guide roll 33 d andthe brake roll 33 a so as to be wrapped around the powder brake 33 for asingle-face web.

Torque of the brake roll 33 a is controlled by the torque adjusting unit33 c under control of a later-described process controller 5A. Suchtorque control can apply braking force of a predetermined strength to asingle-face web 22 wrapped around the brake roll 33 a and atravel-direction tension of a predetermined amount can be generated onthe single-face web 22.

Next, the suction brake 32 for a single-face web will be described. Thesuction brake 32 for a single-face web affects suction force serving asbraking force on a traveling single-face web 22 and is arranged in sucha posture that the suction opening 32 a faces the travel path of thesingle-face web 22, as shown in FIG. 19. The suction opening 32 a islinked to a non-illustrated suction source. The process controller 5Aadjusts, for example, an opening amount of a valve disposed on a suctionline between the suction brake 32 for a single-face web and thenon-illustrated suction source or a load on the suction source, andthereby controls a travel-direction tension of a single-face web 22 tobe a predetermined strength.

The mill brake 30 of the top-liner mill stand M3 also applies a topliner 23 to braking force by controlling torque of the mill roll for thetop liner 23 in the same manner performed for the above powder brakes 31and 33.

The production management machine 2A appropriately controls each brakedevice and corrects warp of a corrugated board sheet 25. Focusing on afunction for warp correction, the production management machine 2Aincludes an acquaintance database 3A, a control variable calculatingsection 4A, the process controller 5A and a warp status inputtingsection 6A, as shown in FIG. 17.

The acquaintance database 3A retains setting values of control variables(adjustment variations from the current values) associated with one ormore particular control factors that affect warp in the travel directionof a corrugated board sheet 25 which particular control factors areamong control factors used to control the corrugated-board fabricationmachine 1, or formulae used to determine the control variables thatcorrelate with warp status (warp direction, a warp extent) in the traveldirection of the corrugated board sheet 25. The particular controlfactors herein are control factors that affect travel-direction tensionsof a single-face web 22 and a top liner 23, and more specifically arebraking force of the above-described mill brake 30 for a top liner 23,powder brakes 31 and 33, braking force of the above suction brake 32 fora single-face web, and the like.

For example, when a corrugated board sheet 25 has upward warp in thetravel direction (has a convex surface toward a top liner 23), a settingvalue or a formula of each control variable is defined in order toincrease a travel-direction tension of the top liner 23 and/or decreasea travel-direction tension of the single web 22. Conversely, when thecorrugated board sheet 25 has downward warp in the travel direction (hasa convex surface toward the single web 22), a setting value or a formulaof each control variable is defined in order to increase atravel-direction tension of the single-face web 22 and/or decrease atravel-direction tension of the top liner 23.

A setting value or a formula of each control variable is defined inaccordance with a predetermined priority order, which is a priorityorder for outputs. For example, when a warp extent is small, onlycontrol variables with higher priorities are output; and when a warpextent is getting larger, other control variables are additionallyoutput in accordance with the priority order. In relation to thepriority order, control factor that more largely affects warp, i.e., acontrol factor that more largely contributes to warp correction, gets ahigher priority.

A table FIG. 20 shows the configuration of the acquaintance database 3Aaccording to the ninth embodiment. In the illustrated example, six warpstatus types of large upward warp, medium upward warp, small upwardwarp, large downward warp, medium downward warp and small downward warpare set correspondingly to the number of push buttons that is to bedescribed later. For each of the warp state types, control variablesthat are to be output are defined in accordance with a priority order.In this embodiment, control factors (particular control factors) arebraking force of the mill brake 30 for a top liner 23, braking force ofeach of the powder brakes 31 and 33, and braking force of the suctionbrake 32 for a single-face web. When a corrugated board sheet 25 hasupward warp, braking force of the mill brake 31 for a top liner 23 isgiven the first priority and a braking force of the mill brake 30 for atop liner is given the second priority. On the contrary, when acorrugated board sheet 25 has downward warp, a braking force of thepowder brake 33 for single-face web is given the first priority and thebraking force (a suction pressure) of the suction brake 32 forsingle-face web is given the second priority.

In FIG. 20, control factors with a triangle (Δ), a circle (∘) or adouble circle (⊚) are outputs when a corrugated board sheet is in acorresponding warp status. A triangle, a circle and a double circlerepresent largeness of a control variable (adjustment variation from thecurrent values). When the three marks of the same control factor arecompared, a circle represents a larger control variable than a triangleand a double circle represents a larger control variable than a circle(Δ<∘<⊚). Accordingly, in this embodiment, if a corrugated board sheet 25has small upward warp for example, only braking force of the powderbrake 31 for a top liner is controlled; if the corrugated board sheet 25has medium warp, an adjustment amount of the powder brake 31 for a topliner is increased and the braking force of the mill brake 30 isadditionally adjusted; and corrugated board sheet 25 has large warp,adjustment amounts of braking force of the powder brake 31 for a topliner and the mill brake 30 are increased. Specific setting values ofcontrol factors and formulae to derive the setting values are defined byexperiments and simulations.

In this embodiment, a warp status of a corrugated board sheet 25 ismanually input to the warp status inputting section (warp statusinformation obtaining means) 6 by an operator. The warp status inputtingsection 6 includes six push buttons 61 (large upward warp), 62 (mediumupward warp), 63 (small upward warp), 65 (large downward warp), 66(medium downward warp) and 67 (small downward warp), each of whichassociates with a warp status classified by the acquaintance database 3,and a reset button 64. An operator depressing a corresponding buttoninputs a selection signal to the control variable calculating section4A. A warp status of a corrugated board sheet 25 is judged by anoperator as a result of visual observation on the corrugated board sheet25 stacked in the stacker 19.

The control variable calculating section 4A retrieves and reads asetting variable or a formula to deriver the variable of eachcorresponding control factor from the acquaintance database 3A on thebasis of the selection signal received from the warp status inputtingsection 6A, and calculates each control variables associated with amachine state (a running state) of the corrugated-board fabricationmachine 1. In the illustrated embodiment, the control variablecalculating section 4A and the acquaintance database 3A serves as thecontrol factor selecting means and the control variable calculatingmeans of the present invention.

A machine state represents current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of webs), brakingforce (exactly, electric current values of torque adjusting units) ofthe powder brakes 31 and 33, braking force of mil brake 30 and brakingforce (precisely, an opening amount of the valve disposed at the suctionpressure line) of the suction brake 32 for a single-face web. Thesevalues of the machine state is input from the process controller 5A,which is to be described later.

When the reset button 64 is selected in the warp status inputtingsection 6A, the control variable calculating section 4A instructs theprocess controller 5A to return all the control factors to the original(values determined by matrix control based on production stateinformation such as a base-board composition, a basis weight of the baseboard, the width of a corrugated board sheet, a flute and the like) Theprocess controller 5A overall controls each of the elements thatconstitute of the corrugated-board fabrication machine 1. The processcontroller 5A usually controls each of elements 10-19 by performingmatrix control based on production state information. However, when onefrom the push buttons 61-63 and 65-57 is depressed in the warp statusinputting section 6A, the process controller 5A controls each of thecontrol factors (here, one or an arbitrary combination of braking forceof brakes 30-33) using one or more control variables calculated by thecontrol variable calculating section 4A. When the reset button 64 isdepressed, the process controller 5A controls elements 30-33 to returnall the control factors to the original. The process controller 5Aalways grasps a current machine state of the corrugated-boardfabrication machine 1, and outputs the current machine state to thecontrol variable calculating section 4A regularly or in response to arequest from the control variable calculating section 4A. Namely, theprocess controller 5A serves as the control means and the running-stateinformation obtaining means according to the present invention.

A succession of procedural steps of correcting warp of a corrugatedboard sheet performed by the above-described production managementmachine 2A is substantially identical to that of the first embodiment,which has been explained with reference to flow diagram FIG. 6.

Namely, first of all, the production management machine 2A checks amachine state at step A10 and checks a production state at step A20. Inthe ensuing step A30, the production management machine 2 judges whetheror not a warp status can be currently input (one from the push button61-67 can be input). The judgment is made so as not to correct warpwhile another trouble arises because warp correction is useless whensuch another problem, e.g., a low rate of web travel due to anexcessively strong glue adhesive, arises.

If a warp status can be input at step A30, the production managementmachine 2 judges whether or not a warp status has been actually input atstep A40. If a warp status has been input, the production managementmachine 2A selects one or more control factors (here, one or anarbitrary combination of braking forces of brakes 30-33) in accordancewith a priority order of the input warp status, i.e., the selected oneof the push buttons 61-63 and 65-67.

In succession at step A60, the production management machine 2 refers tothe acquaintance database 3A and calculates one or more controlvariables associated with the machine state obtained in step A10. Atthis time, production management machine 2A may use the production stateinformation obtained at step A20 as reference data, for example, inorder to change wrap amounts considering base paper composition (thickpaper, thin paper). The production management machine 2A outputs thecalculated control variables to corresponding elements (here, one or anarbitrary combination of braking forces of brakes 30-33) at step A70.

According to the system for correcting a possible warp of a corrugatedboard sheet of the illustrated embodiment, braking force of the brakes30-33 which forces affect warp of a corrugated board sheet 25 isautomatically adjusted in the production management machine 2A by anoperator visually judging a warp status of a corrugated board sheet 25fabricated in the corrugated-board fabrication machine 1 and simplydepressing one of buttons 61-63 and 65-67, whichever one corresponds toa warp status. Thereby, it is possible to accurately correct warp ofcorrugated board sheets with ease without depending on experience of anoperator and know-how.

Since one or more control factors are selected based on an amount ofwarp (here, one or more control factors are additionally selected inaccordance with a priority order, considering an extent of warp of acorrugated board sheet 25), it is possible to effectively correct warpirrespective of a warp amount. In particular in this embodiment, it ispossible to correct warp of a corrugated board sheet 25 faster byproviding a control factor that more largely affects the warp with ahigher priority.

In the present ninth embodiment, warp of a corrugated board sheet 25 iscorrected using braking force of the brakes 30-33 as control factors.These control factors are only one example and a greater number ofcontrol factors to be controlled may be used likewise in the followingtenth embodiment.

(B-2) Tenth Embodiment

FIG. 21 shows a system for fabricating a corrugated board sheetaccording to the tenth embodiment of the present invention.

The corrugated-board fabrication machine 1 of this embodiment includes awrap roll 40 for a top liner 23 (a top liner wrap roll) and a wrap roll41 for a single-face web 22 (a wrap roll for a single-face web) inaddition to the parts and elements of the corrugated-board fabricationmachine 1 of the ninth embodiment shown in FIG. 17. Here, the wrap roll40 for a top liner is disposed between the top liner preheater 14 andthe double facer 16, and the wrap roll 41 for a single-face web isdisposed between the single-face web preheater 13 and the glue machine15.

The wrap roll 41 for single-face web will now be illustrated withreference to FIG. 22 to explain the wrap rolls 40 and 41. Guide rolls 41a and 41 b are arranged close to the wrap roll 41 for a single-face weband are disposed upstream and downstream of the wrap roll 41 for asingle-face web. A single-face web 22 travels the space between the wraproll 41 for single-face web and each of the guide rolls 41 a and 41 b soas to be wrapped around the wrap roll 41 for a single-face web.

One of the guide rolls 41 a is fixed to the tip of an arm 41 c, which isswingably attached to the axis of the wrap roll 41 for a single-faceweb. The arm 41 c is driven by a non-illustrated motor, and acombination of the guide roll 41 a and the non-illustrated motor servesas a wrap amount adjusting unit. In other words, the motor drives thearm 41 c to turn the guide roll 41 a to a desired position whereupon itis possible to adjust a wrap amount of a single-face web 22 around thewrap roll 41 for a single-face web. An increase of the above wrap amountincreases the running resistance of the single-face web 22 so that thetravel-direction tension of the single-face web 22 is increased. On theother hand, a decrease of the above wrap amount reduces thetravel-direction tension of the single-face web 22.

Any position upstream of the double facer 16 is satisfactory to placethe wrap roll 40 for a top liner and any position upstream of the gluemachine 15 is satisfactory to place the wrap roll 41 for a single-faceweb.

FIG. 23 shows the configuration of the acquaintance database 3Aaccording to the tenth embodiment of the present invention.

Focusing on a function for warp correction, the present embodimentincludes control factors of wrap amounts of a web around the wrap rolls40 and 41 in addition to the control factors of the ninth embodiment. Inorder to correct upward warp, braking force of the powder brake 31 for atop liner, braking force of the mill brake 30 for a top liner, and thewrap roll 40 for a top liner are respectively given the first, thesecond and the third priorities in the same manner as the ninthembodiment. For downward warp, braking force of the powder brake 33 fora single-face web, braking force of the suction brake 32 for asingle-face web, and wrap roll 41 for single-face web are respectivelygiven the first, the second and the third priorities similarly to theninth embodiment.

The remaining configuration thereof is identical to that of the ninthembodiment, so repetitious description will be omitted.

As a result, the system for correcting possible warp of a corrugatedboard sheet according to the illustrated embodiment can perform moredetail management and more accuracy warp correction of a corrugatedboard sheet 25 than the ninth embodiment because of the greater numberof control factors than the ninth embodiment.

(B-3) Eleventh Embodiment

An eleventh embodiment of the present invention will now be describedwith reference to FIGS. 24-26. The present embodiment is featured bymeans to obtain information about a warp status of a corrugated boardsheet 25 and the remaining configuration is identical to the ninthembodiment shown in FIG. 21.

As shown in FIG. 24, the production management machine 2A of thisembodiment comprises a warp status judgment section 8A as a substitutefor the warp status inputting section (push buttons) 6 of the ninthembodiment. A CCD camera (imaging means) 7 is arranged at the rearmostsection of the corrugated-board fabrication machine 1.

As shown in FIG. 25, the CCD camera 7 is arranged at a stacking section192 of the stacker 19. Corrugated board sheets 25 are cut by the cut-offdevice 18, transferred by a plurality of non-illustrated conveyors 191,and then subsequently piled in the stacking section 192. The CCD camera7 images the side of corrugated board sheets 25 piled in the stackingsection 192 along the travel direction and outputs the image data to thewarp status judgment section 8.

The warp status judgment section 8A performs image processing on theimage data and measures the heights of three points (both ends and thecenter) of a corrugated board sheet 25 which points are arranged in thetravel direction. Then the warp status judgment section 8 judges a wrapdirection (upward or downward) along the travel direction and a heightextent (large, medium or small) on the basis of the variance of themeasured heights. The result of the judgment is sent to the controlvariable calculating section 4A, which then selects a control factorbased on the judgment result and calculates a control variable of theselected control factor in accordance with machine state informationwith reference to the acquaintance database 3A.

Here, the judgment of a warp status by the warp status judgment section8 will now be specifically described with reference to FIGS. 26 a and 26b. The CCD camera 7 photographs a travel-direction side of a corrugatedboard sheet 25 as shown in FIG. 26 a. The warp status judgment section 8performs image processing on image data from the CCD camera 7 andcalculates vertical variations d, s and a of predetermined three points(the upstream corner PD, the web center PS and the downstream corner PA)arranged in the travel direction with respect to the reference line LO.

The warp status judgment section 8 calculates vertical curl-up amountsA2 and D2 of the corners PD and PA with respect to a flat floor,assuming that a corrugated board sheet 25 is placed on a flat floor, onthe basis of the vertical variation d, s and using the followingformulae (6) and (7). Further, the warp status judgment section 8calculates an amount WF_(MD) of warp along the travel direction definedin terms of the formula (8) below using the vertical curl-up amounts A2and D2. The warp direction is judged by positiveness and negativeness ofthe warp amount WF_(MD), and the warp height is determined by thelargeness of the absolute value of the warp amount WF_(MD).$\begin{matrix}{{A\quad 2} = {s - a}} & (6) \\{{D\quad 2} = {s - a}} & (7) \\{{WF}_{MD} = {\frac{\left( {{A\quad 2} + {D\quad 2}} \right)}{2} \times \frac{\alpha}{W^{2}}}} & (8)\end{matrix}$

-   -   where, W represents the length of the width of a corrugated        board sheet 25, and a is α constant used to make a warp amount        dimentionless.

In the system for correcting possible warp of a corrugated board sheetaccording to this embodiment, warp of a corrugated board sheet 25 isautomatically corrected so that it is possible to accurately correcttravel-direction warp of corrugated board sheets with ease withoutdepending on experience of an operator and know-how. In the illustratedexample, the usage of the acquaintance database 3A according to theninth embodiment classified a warp extent that had been determined intolarge, medium and small. It is possible for this system to judge a warpextent more sensitively so that warp of a corrugated board sheet 25 canbe corrected more accurately.

(B-4) Twelfth Embodiment

FIG. 27 schematically shows the main part of the corrugated-board warpdetection unit according to a twelfth embodiment.

In the above eleventh embodiment described with reference to FIG. 24,the warp status judgment section 8A obtains a warp status of acorrugated board sheet 25 based on image data obtained by the CCD camera7. This embodiment uses variation sensors (variation amount detectingmeans) 7A and 7B as a substitute for the CCD camera (imaging means) 7 sothat a warp status judgment section 8A obtains a status of possible warpof a corrugated board sheet based on measurement data obtained by thevariation sensor 7A, 7B.

As shown in FIG. 27, the variation sensor 7A is slidably attached to therail 171 a, which extends horizontally along the width direction of acorrugated board sheet 25, through a variation sensor mounting member172 a, the rail 171 a being slidably attached to a rail 171 b, which isfixed to an upper frame 171 at the stacking section 192 through avariation sensor mounting member 172 b and which horizontally extends inthe travel direction of the corrugated board sheet 25.

Non-illustrated driving means is attached to the variation sensormounting members 172 a and 172 b. The variation sensor 7A is driven bythe driving means so that the variation sensor 7A can horizontally movealong the width and travel directions of a corrugated board sheet 25.Thereby, as shown in FIG. 28, the variation sensor 7A is a control to bepositioned over a measurement point PD near the upstream corner on thedriving side of a corrugated board sheet 25, a measurement point PC nearthe upstream corner on the operating side, a measurement point PS nearthe center of the driving-side end in the travel direction and ameasurement point PR near the center of the operating-side end in thetravel direction. It is possible to obtain vertical variation amounts c,d, r, and s of the points PC, PD, PR and PS, respectively, with respectto the variation sensor.

Meanwhile, as shown in FIG. 27, the variation sensor 7B is slidablyattached to a rail 173 a, which is fixed to the frame 171 and whichhorizontally extends along the width direction of a corrugated boardsheet 25, through a variation sensor mounting member 174 a, whichincludes non-illustrated driving means. The variation sensor 7B isdriven by this driving means and can horizontally move along the widthdirection of a corrugated board sheet 25. Thereby, the variation sensor7B is controlled to be positioned above a measurement point PA near thedownstream corner on the driving side of a corrugated board sheet 25 anda measurement point PB near the downstream corner on the operating sideof the corrugated board sheet 25 shown in FIG. 28. It is possible toobtain vertical variation amounts a and b of the respective points PAand PB with respect to the variation sensor.

Then the warp status judgment section 8 obtains a warp amount WF_(MD) inthe travel direction based on the difference of the vertical variationamounts of both ends of a web in the travel direction with respect tothe centers in the travel direction by using the following formula (9).Here, the warp status judgment section 8 regards the vertical variationamount s of point PS at the center of the driving side in the traveldirection as a reference to obtain a travel-direction warp amount on thedriving side, regards the vertical variation amount r of point PR at thecenter of the operating side in the travel direction as a reference toobtain a warp amount of the operating side in the travel direction andthen calculate a warp amount WF_(MD) in the travel direction of acorrugated board sheet 25 by using the average of the abovetravel-direction warp amounts as shown in the formula (9).$\begin{matrix}{{WF}_{MD} = {{\frac{1}{2}\left\lbrack {\left\{ {s - \frac{a + d}{2}} \right\} + \left\{ {r - \frac{b + c}{2}} \right\}} \right\rbrack} \times \frac{\alpha}{W^{2}}}} & (9)\end{matrix}$

The remaining configuration is identical to that of the ninthembodiment, so any repetitious description is omitted here.

As a result, the system for correcting possible warp of a corrugatedboard sheet according to the present embodiment guarantees the sameadvantages as the eleventh embodiment.

In order to obtain warp WF_(MD) of the travel direction, it is enough toobtain a vertical variation amount along the travel direction of acorrugated board sheet 25. For example, the simple configuration toobtain vertical variation distributions p, t, and q of the three pointsPP, PT, and PQ shown in FIG. 29 may be satisfactory. In this case, thewarp amount WF_(MD) is calculated by using the following formula (10),for example. $\begin{matrix}{{WF}_{MD} = {{\frac{1}{2}\left\lbrack {\left( {t - p} \right) + \left( {t - q} \right)} \right\rbrack} \times \frac{\alpha}{W^{2}}}} & (10)\end{matrix}$

Further, in the illustrated embodiment, the variation sensor 7A, 7Bdetect vertical variation amounts at the stacking section 192 of thestacker 19. Detecting vertical variation amounts on a corrugated boardsheet 25 serving as a final product, the overall width of which has beencut by the cut-off device 18 is satisfactory. In other words, asatisfactory variation sensor detects vertical variation amounts of acorrugated board sheet 25 at any point down stream of the cut-off device18. For example, a variation sensor may be arranged over a conveyerbetween the cut-off device 18 and the stacker 19 so that variationdetecting is performed on a corrugated board sheet 25 being transferredon the conveyer.

(B-5) Others

The ninth to twelfth embodiments of the present invention are describedin the above. But the present invention should by no means be limited tothese embodiments and another alternation and modification can besuggested without departing from the concept of the present invention.

For example, the eleventh embodiment shown in FIG. 24 includes the warpstatus judgment section 8 and the CCD camera (imaging means) 7 as asubstitute for the warp status inputting section (push buttons) 6A ofthe ninth embodiment shown in FIG. 17; and the twelfth embodiment shownin FIG. 27 includes the warp status judgment section 8 and the variationsensors (variation amount detecting means) 7A and 7B as a substitute forthe warp status inputting section (push buttons) 6A of the ninthembodiment. Alternatively, the tenth embodiment shown in FIG. 21 may bemodified to include the warp status judgment section 8A and the CCDcamera (imaging means) 7 as a substitute for the warp status inputtingsection (pushbuttons) 6A or to include the warp status judgment section8 and the variation sensors (variation amount detecting means) 7A and 7Bas a substitute for the warp status inputting section (push buttons) 6A.

In the ninth to twelfth embodiments, the brake devices 30-33 and thewrap rolls 40 and 41 are used as particular control factors. Anothercontrol factor that affects the travel-direction tension of a top liner23 or a bottom liner 20 can be used as a particular control factor tocorrect warp of a corrugated board sheet 25. Therefore, theconfigurations of the acquaintance databases 3A described along with theninth and tenth embodiments are only examples, and an acquaintancedatabase 3 may be formed in accordance with particular control factorsthat are to be used. A priority order thereof should by no means belimited to those of the embodiments and may be arbitrarily set.

(C)

Hereinafter is a description of systems for correcting possible warp ofcorrugated board sheet according to the thirteenth to eighteenthembodiments and modifications thereof with reference to FIGS. 30-45.Parts and elements identical to those described in the foregoingembodiments are to be referred to by the same reference numbers.

(C-1) Thirteenth Embodiment

FIG. 30 schematically shows a system for correcting possible warpaccording to the thirteenth embodiment of the present invention. Thesystem for correcting possible warp of the thirteenth embodimentincludes a corrugated-board fabrication machine 1 and a productionmanagement machine 2B to manage the corrugated-board fabrication machine1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by a medium web preheater12 and then glue the medium web 21 to the bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat asingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13, a double facer 16′ tofabricate a corrugated board 24 by gluing the single-face web 22 pastedby the glue machine 15 to a top liner 23 heated by the top linerpreheater 14, a slitter scorer 17 to slit and score the corrugated board24 fabricated by the double facer 16′, a cut-off device 18 to make afinal product (a corrugated board sheet) 25 by dividing a corrugatedboard 24 scored and subjected to another procedure by the slitter scorer17 into separated forms, and a stacker 19 to sequentially stackcorrugated board sheets 25 in a fabricated order.

Among the parts and elements 10-19, the double facer 16′ affects atension distribution in the width direction of a web (is able to adjusta tension distribution in the width direction of a web). The structureof the double facer 16′ of this embodiment is partially different fromthat of the double facer 16 shown in FIG. 4. Hereinafter, the doublefacer 16′ will now be described with reference to FIG. 31. The doublefacer 16′ is divided into an upstream heating section 16A and adownstream cooling section 16B which sections lie along the travel pathof a single-face web 22 and a top liner 23. In the heating section 16A,a plurality of hotplates 162 are arranged and a top liner 23 passes onthese hotplates 162. Vapor supplied to the inside of each hotplate 162heats the hotplate 162 to a predetermined temperature.

On the hotplates 162, a loop-shaped press belt 163 interposed by thetravel path runs in synchronization with a single-face web 22 and a topliner 23. A plurality of press rolls (press means) 264 are disposedwithin the loop formed by the press belt 163 so as to be opposite to thehotplates 162 (i.e., in such a posture that the press rolls 264 face thehotplates 162 and that the rotating axis of the press rolls 264 areparallel to the surface of the hotplates 162). Press rolls 264A, whichis the upstream half of the press rolls 264, include rotation mechanismsto rotate keeping parallel relationship with the hotplates 162 andchange tilt angles of the press rolls 264A with respect to the widthdirection of a web.

Namely, as shown in plain view FIG. 32, a supporting member 264 c, whichrotatably supports a end 264 a of one rotating axis of press roll 264A,is rotatably supported around the rotating axis by a non-illustratedframe, and a supporting member 264 d, which rotatably supports a end 264b of the other rotating axis, is swingably connected to the piston rodof a fluid pressure cylinder 264 e. Variation of the length of thepiston rod of the fluid pressure cylinder 264 e moves the press roll264A circlewise around the supporting member 264 c to thereby change thetilt angles with respect to the width direction of a web. A fluidpressure cylinder 264 e is supported by a non-illustrated frame.

A single-face web 22 pasted in the glue machine 15 is introduced into aspace between the press belt 163 and the hotplates 162 so as to be incontact with the press belt 163 while a top liner 23 heated by the topliner preheater 14 is further preheated by the liner entrance preheatingroll 165 and is then introduced into the space between the press belt163 and the hotplates 162 from the hotplates-162 side (so as to be incontact with the hotplates 162). After being introduced into the spacebetween the press belt 163 and the hotplates 162, the single-face web 22and the top liner 23 pile up to form one body and are transferred to thecooling section 16B. While the single-face web 22 and the top liner 23are transferred, the single-face web 22 and the top liner 23 are pressedby the pressure rolls 264 being interposed by the press belt 163 and areheated from the top-liner-23 side whereupon the single-face web 22 andthe top liner 23 are glued together to form a double-face web 24. Theoverall width or the edge of the double-faced web 24 is cut by a rotaryshear installed at the exit of the cooling section 16B and then thedouble-faced web 24 is transferred to the slitter scorer 17 at which theensuing step is to be performed.

The production management machine 2B shown in FIG. 30 appropriatelycontrols a width-direction tension distribution of a corrugated boardsheet 25 in order to correct twist warp of corrugated board sheets 25.Focusing on a function for correcting warp of corrugated board sheets25, the production management machine 2B, as shown in FIG. 30, comprisesan acquaintance database 3B, a control variable calculating section 4B,a process controller 5B and a warp status inputting section 6B.

The acquaintance database 3B retains setting values of control variables(adjustment variations from the current values) associated with one ormore particular control factors that affect the possible twist warp of acorrugated board sheet 25 which particular control factors are amongcontrol factors used to control the corrugated-board fabrication machine1, or formulae used to determine the control variables that correlatewith a twist warp status (a warp pattern and/or a warp amount) of thecorrugated board sheet 25. Here, particular control factors are the tiltangles of the press rolls 264A in the above-described double facer 16′and the like.

When a tension on the operating side of a corrugated board sheet 25 isgreater than that on the driving side, the corrugated board sheet 25 hastwist warp A shown in FIG. 33 a (resulting in large vertical variation(curl) amounts at the downstream corner PB on the operating side and atthe upstream corner PD on the driving side, that is the diagonal cornerof the corner PB). Therefore, in order to reduce such twist warp A, theacquaintance database 3B defines a setting value or a setting formula ofa control variable for a tilt angle θ (specifically, a stroke amount ofthe piston rod of the fluid pressure cylinder 264 d(see FIG. 32)) usedto, for example, rotate press rolls 264A from the position indicated bya solid line in FIG. 33 c to the position indicated by the double-dottedbroken line therein (i.e., to move the operating side of the press roll264A downstream with respect to the rotating axis) so that the tensionon the operating side of the corrugated board sheet 25 is reduced.

On the other hand, when a tension on the driving side of a corrugatedboard sheet 25 is greater than that on the operating side, thecorrugated board sheet 25 has twist warp B shown in FIG. 33 b (resultingin large vertical amounts at the downstream driving-side corner PA andat the upstream operating-side corner PC, that is diagonal corner of thecorner PA). Therefore, in order to reduce such twist warp B, theacquaintance database 3B defines a setting value or a setting formula ofa control variable of a tilt angle θ used to, for example, rotate apress roll 264A from the position indicated by a solid line in FIG. 33 dto the position indicated by the double-dotted broken line therein(i.e., to move the operating side of the press rolls 264A upstream withrespect to the rotating axis 264 a) so that the tension on the operatingside of the corrugated board sheet 25 is increased.

FIG. 34 shows the configuration of the acquaintance database 3Baccording to this embodiment. Here, six warp status types of twist warpA (large), twist warp A (medium), twist warp A (small), twist warp B(large), twist warp B (medium) and twist warp B (small) are setcorresponding to the number of push buttons that are to be describedlater. For each of the warp status types, a tilt angle θ of the pressrolls 264A, which angle serves as a particular control factor, iscontrolled.

Specifically, a triangle, a circle and a double circle representlargeness of control variables (adjustment variations from the currentvalues). When the three marks of the same control factor are compared, acircle represents a larger control variable than a triangle and a doublecircle represents a larger control variable than a circle (Δ<∘<⊚).Accordingly, in this embodiment, if a corrugated board sheet 25 hassmall twist warp A, the tilt angle θ is adjusted such that the operatingside of the press roll 264A comes forward (moves downstream in thetravel direction); if a corrugated board sheet 25 has medium twist warpA, the tilt angle θ is adjusted such that the operating side of thepress roll 264A comes forward more than the case of small twist warp A;and if a corrugated board sheet 25 has large twist warp A, the tiltangle θ is adjusted such that the operating side of the press roll 264Acomes forward more than the case of medium twist warp A. Definiteadjustment setting values and setting formulae are defined byexperiments and simulations.

In this embodiment, a warp status of a corrugated board sheet 25 ismanually input to the warp status inputting section (warp statusinformation obtaining means) 6 by an operator. The warp status inputtingsection 6B includes six push buttons 61 (large twist warp A (largewarp)), 62 (medium twist warp A (medium warp)), 63 (small twist warp A(small warp)), 65 (large twist warp B (large warp)), 66 (medium twistwarp B (medium warp)) and 67 (small twist warp B (small warp)), each ofwhich associates with a warp status classified by the acquaintancedatabase 3, and a reset button 64. An operator depressing acorresponding button inputs a selection signal to the control variablecalculating section 4B. A warp status of a corrugated board sheet 25 isdetermined by an operator as a result of visual observation on thecorrugated board sheet 25 stacked in the stacker 19.

The control variable calculating section 4B retrieves and reads asetting variable or a formula to deriver the variable of eachcorresponding control factor from the acquaintance database 3B on thebasis of the selection signal received from the warp status inputtingsection 6B, and calculates each of the control variables associated witha machine state (a running state) of the corrugated-board fabricationmachine 1. In the illustrated embodiment, the control variablecalculating section 4B and the acquaintance database 3B serve thecontrol variable calculating means of the present invention.

A machine state represents the current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of a web), a tiltangle θ of the press roll 264A and so on. These values of the machinestate are input from the process controller 5B, which is to be describedlater.

When the reset button 64 is selected in the warp status inputtingsection 6B, the control variable calculating section 4B instructs theprocess controller 5B to return all the control factor to the originals(values determined by matrix control based on production stateinformation such as a base-board composition, a basis weight of the baseboard, the width of a corrugated board sheet, a flute and the like) Theprocess controller 5B overall controls each of the elements 10-19 thatconstitute the corrugated-board fabrication machine 1. The processcontroller 5B usually controls each of elements 10-19 by performingmatrix control based on production state information. However, when onefrom the push buttons 61-63 and 65-57 is depressed in the warp statusinputting section 6A, the process controller 5 controls each of thecontrol factors (here, the tilt angle θ of the press rolls 264A) usingone or more control variables calculated in the control variablecalculating section 4B. When the reset button 64 is depressed, theprocess controller 5B controls elements 10, 13, and 14 to return all thecontrol factors to the originals. The process controller 5B alwaysgrasps a current machine state of the corrugated-board fabricationmachine 1, and outputs the current machine state to the control variablecalculating section 4B regularly or in response to a request from thecontrol variable calculating section 4B. Namely, the process controller5B serves the control means and the running-state information obtainingmeans of the present invention.

The flow diagram in FIG. 35 describes a succession of procedural stepsof correcting warp of a corrugated board sheet 25 using theabove-described functions of the production management machine 2B.

First of all, the production management machine 2B checks a machinestate at step B10 and checks a production state at step B20. In theensuing step B30, the production management machine 2 judges whether ornot a warp status can be currently input (one from the push button 61-67can be input). The judgment is made so as not to correct warp whileanother trouble arises because warp correction is useless when suchproblem, e.g., a low rate of web travel due to an excessively strongadhesive, arises.

If a warp status can be input at step B30, the production managementmachine 2B judges whether or not a warp status has been actually inputat step B40. If a warp status has been input, the production managementmachine 2B calculates a control variable of each control factor (here,the tilt angle θ of the press rolls 264A) to be controlled in accordancewith the input warp status by referring to the acquaintance database 3Bon the basis of the machine state information obtained in step B10, atstep B50. At that time, the production state information obtained instep B10 may be used as reference data in order to, for example, changethe tilt angle θ in accordance with the base paper composition (thickpaper, thin paper) that is data obtained in step B20. The productionmanagement machine 2B outputs the calculated control variable to thecorresponding element at step B60.

According to the system for correcting possible warp of a corrugatedboard sheet of the first embodiment, the tilt angle angle θ of the pressrolls 264A which angle affects twist warp of a corrugated board sheet 25is automatically adjusted by the production management machine 2B inresponse to an operator visually judging a warp status of a corrugatedboard sheet 25 fabricated in the corrugated-board fabrication machine 1and simply depressing one of buttons 61-63 and 65-67, the onecorresponding to a warp status. Thereby, it is possible to accuratelycorrect warp of corrugated board sheets with ease without depending onexperience and know-how of an operator.

In this thirteenth embodiment, the tilt angle θ of the press rolls 264Ais explained as a control factor to correct possible warp of corrugatedboard sheets 25. The tilt angle θ is only an example, and a greaternumber of control factors to be controlled may be used likewise in thefollowing fourteenth embodiment.

Further, in the illustrated example, the tilt angle θ of the half of thepress rolls 264A can be changed. However, a satisfactory double facer16′ has at least one press the tilt angle of which can be changed.

(C-2) Fourteenth Embodiment

A corrugated-board fabrication system according to the presentembodiment includes, differently from the thirteenth embodiment, apressure variable mechanism to vary a pressure to be applied to a web inthe web-width direction at the each downstream press roll 264B of thedouble facer 16′ shown in FIG. 31. Namely, as shown in the front viewFIG. 36, supporting members 264 f and 264 f respectively support theends 264 a and 264 b of the rotating axis of each press roll 264B areswingably fixed to the ends of piston rods of fluid pressure cylinders264 g, which are attached to a frame (not shown).

With this structure, an increase in fluid pressure to be applied to thefluid pressure cylinder 264 g arranged on the driving side increasespressure applied to the driving side of a single-face web 22 and a topliner 23 being transferred in the double facer 16′ and thereby increasesdriving-side tensions of the webs 22 and 23. In the same manner, anincrease in fluid pressure to be applied to the other fluid pressurecylinder 264 f arranged on the operating side increases pressure appliedto the operating side of the webs 22 and 23 and thereby increasesdriving-side tensions of the webs 22 and 23. The fluid pressure to beapplied to each fluid pressure cylinder 264 f is controlled by adjustinga pressure adjusting valve placed at a pipe to provide the fluidpressure cylinder 264 f with fluid.

Table FIG. 37 illustrates the configuration of an acquaintance database3B according to the fourteenth embodiment of the present invention.

Focusing on warp correction, a width-direction distribution of apressure to be applied to the above press rolls 264B is assigned as aparticular control factor in addition the control factors used in thethirteenth embodiment. Here, a priority order of control factors to beoutput is determined in association with each of the above-describedpush buttons (i.e., a warp status of a corrugated board sheet 25). Thepriority order represents an output order. For example, if a corrugatedboard sheet 25 has small extent warp, only control factors of higherpriority order are output; and other control factors are determined tobe sequentially output in the priority order as warp extent becomeslarger. A priority order gives a control factor having a greater effecton warp, in other words, a control factor having a higher capability ofwarp correction, a higher priority.

Specifically, an adjustment of the tilt angle θ of the press rolls 264Ais given the first priority and an adjustment of the width-directiondistribution of a pressure from the press rolls 264B is given the secondpriority. When a corrugated board sheet 25 has small twist warp A, thetilt angle θ of the press rolls 264A is adjusted such that the operatingside of the press rolls 264A come forward in order to decrease anoperating-side tension of the corrugated board sheet 25 or increase adriving-side tension. When a corrugated board sheet 25 has medium twistwarp A, an adjustment amount of the tilt angle θ is increased andconcurrently the pressures applied by the driving side of the pressrolls 264B are also increased; and when the twist warp A is large, theadjusting amounts (control variables) of both the tilt angle θ and theapplied pressures are increased.

Conversely, when a corrugated board sheet 25 has small twist warp B, thetilt angle θ of the press rolls 264A is adjusted such that the operatingside of the press rolls 264A comes backward in order to increase anoperating-side tension of the corrugated board sheet 25 or to decrease adriving-side tension. When a corrugated board sheet 25 has medium twistwarp B, the adjustment amount of the tilt angle θ is increased andconcurrently the pressures applied by the operating side of the pressrolls 264B are also increased; and the twist warp B is large, theadjustment amounts of both the tilt angle θ and the applied pressuresare increased.

A control variable of a particular control factor that has been selectedin the above manner is calculated by the control variable calculatingsection 4B. In the illustrated embodiment, the control variablecalculating section 4B and the acquaintance database 3B serve as thecontrol factor selecting means and the control variable calculatingmeans of the present invention.

According to the system for correcting possible warp of a corrugatedboard sheet of this embodiment, since one or more control factors areselected in accordance with an extent of warp (here, one or more controlfactors are additionally selected in accordance with a priority order,considering an extent of warp of a corrugated board sheet 25), it ispossible to accurately correct warp irrespective of a warp extent. Inparticular in this embodiment, it is possible to correct warp of acorrugated board sheet 25 faster by providing a control factor that morelargely affects the warp with a higher priority.

As a substitute for the press rolls 264A and/or the press rolls 264B, aplurality of press units (press means) each of which is formed by a shoeand an actuator (e.g., a fluid pressure cylinder) to press the shoe ontoa hotplates 162 may be disposed along the direction of the width of aweb. It is possible to adjust web-width-direction pressures that is tobe applied to a single-face web 22 and a top liner 23 against thehotplates by individually controlling the actuators arranged along theweb width direction. Whereupon the width-direction tension distributioncan be adjusted.

(C-3) Fifteenth Embodiment

Next, the fifteenth embodiment of the present invention will now bedescribed. The corrugated-board fabrication machine 1 of this embodimentincludes a wrap roll 41 for a single-face web 22 (wrap roll for a singleface web) shown in FIG. 22 in addition to elements and parts of thecorrugated-board fabrication machine 1 included in the fourteenthembodiment. In the illustrated embodiment, the wrap roll 41 for asingle-face web is disposed between the single-face web preheater 13 andthe glue machine 15.

As already described with reference to FIG. 22, the guide rolls 41 a and41 b are arranged close to the wrap roll 41 for a single-face web andare disposed upstream and downstream of the wrap roll 41 for asingle-face web. A single-face web 22 travels the space between the wraproll 41 for a single-face web and each of the guide rolls 41 a and 41 bso as to wrap around the wrap roll 41 for a single-face web. The bothends of the rotating axis of the wrap roll 41 for a single-face web arerespectively connected to piston rods of non-illustrated fluid pressurecylinders in the same manner as the press rolls 264B of the double facer16′ so that the heights of the both ends cab be individually changed.With this structure, for example, an upward movement of the driving-sideend of the rotating axis in FIG. 22 increases a web tension on thedriving side; conversely, a downward movement of the operating side ofthe rotating axis in FIG. 22 increases a web tension of the operatingside.

One guide roll 41 a is fixed to the tip of an arm 41 c, which isswingably attached to the axis of the wrap roll 41 for a single-faceweb. The arm 41 c is driven by a non-illustrated motor, and acombination of the guide roll 41 a and the non-illustrated motor servesas a wrap amount adjusting unit. In other words, when the motor drivesthe arm 41 c to turn the guide roll 41 a, a wrap amount of a single-faceweb 22 around the wrap roll 41 for a single-face web is adjusted. Anincrease of the above wrap amount increases the running resistance ofthe single-face web 22 so that the travel-direction tension of theentire width of the single-face web 22 is increased. On the other hand,a decrease of the above wrap amount reduces the travel-direction tensionof the entire width of the single-face web 22.

Further, the transfer path of a top liner 23 may include the same wraproll as the wrap roll 41 at an upstream point of the double facer 16′.Any position upstream of the glue machine 15 is satisfactory to placethe wrap roll 41 for a single-face web.

FIG. 38 shows the configuration of an acquaintance database 3B accordingto the fifteenth embodiment of the present invention.

Focusing on warp correction, in the present embodiment, the heights ofthe both ends of the rotating axis of the wrap roll 41 for a single-faceweb are assigned as particular control factors in addition to eachcontrol factor of the fourteenth embodiment. When a corrugated boardsheet 25 has twist warp A, an adjustment of the tilt angle θ of thepress rolls 264A is given the first priority; an adjustment of theheights of the both ends of the rotating axes of the press rolls 264B isgiven the second priority; and an adjustment of the heights of the bothends of the rotating axis of the wrap roll 41 is given the thirdpriority. The remaining configuration is identical that of thethirteenth embodiment, so repetitious description is omitted here.

According to the system for correcting possible warp of a corrugatedboard sheet of this embodiment, the above control factors that arelarger in number than the fourteenth embodiment can realize managementmore detail than the fourteenth embodiment whereupon warp of acorrugated board sheet 25 can be corrected further accurately.

(C-4) Sixteenth Embodiment

A sixteenth embodiment of the present invention will now be described.FIG. 39 is a plain view schematically showing a suction brake for asingle-face web according to the sixteenth embodiment.

In addition to the corrugated-board fabrication machine 1 of thefifteenth embodiment, the corrugated-board fabrication machine 1 of thepresent embodiment further includes a suction brake 32′ for asingle-face web shown in FIG. 39. Dividing the suction brake 32, whichhas been described with reference to FIG. 19, in the width directionforms the suction brake 32′. The side shape of the suction brake 32′ isidentical to that of the suction brake 32 shown in FIG. 19.

As described above, a suction brake affects suction force, serving asbraking force, on a traveling single-face web 22 and is included in aconventional corrugated-board fabrication machine. A single suctionbrake has been conventionally arranged for a single-face web and brakingforce (suction force) thereof cannot have been adjusted in accordancewith the width direction of a web.

On the other hand, the suction brake 32′ for a single-face web of thisembodiment is formed by a plurality (here, two) of suction boxes 32Aarranged in the web width direction as shown in FIG. 39. Each of thesuction boxes 32A is arranged such that a suction opening 32 a (see FIG.19), which is connected to a non-illustrated suction source, faces totravel path of a single-face web 22. The process controller 5Bindividually controls, for example, an opening amount of a valvedisposed on a suction line between each suction box 32A and the suctionsource to adjust a distribution of a travel-direction tension of thedriving side of a single-face web 22. Specifically, an increase ofdriving-side suction force of the suction brake 32′ for a single-faceweb increase a travel-direction tension of the driving side of asingle-face web 22; and an increase of operating-side suction force ofthe suction brake 32′ for a single-face web increase a travel-directiontension of the operating side of a single-face web 22.

Table FIG. 40 shows the configuration of an acquaintance database 3Baccording to the sixteenth embodiment.

Focusing on warp correction, the present embodiment further includes, asa particular control factor, a distribution of braking force of thesuction brake 32′ for a single-face web in addition to the controlfactors of the fifteenth embodiment. When a corrugated board sheet 25has twist warp A, for example, an adjustment of the tilt angle θ of thepress rolls is given the first priority; an adjustment of awidth-direction distribution of pressure applied by the press rolls 264Bis given the second priority; an adjustment of the heights of the bothends of the rotating axis of the wrap roll 41 is given the thirdpriority; and an adjustment of braking force of the suction brake 32′ isgiven the fourth priority. The remaining configuration is identical tothat of the thirteenth embodiment, so repetitious description is omittedhere.

According to the system for correcting possible warp of a corrugatedboard sheet of this embodiment, the above control factors that arelarger in number than the fifteenth embodiment can realize managementmore detail than the fifteenth embodiment whereupon warp of a corrugatedboard sheet can be corrected further accurately.

(C-5) Seventeenth Embodiment

A seventeenth embodiment of the present invention will now be described.This embodiment is featured by means to obtain information in relationto a warp status of a corrugated board sheet 25 and the remainingconfiguration is identical to that of the thirteenth embodiment.

As shown in FIG. 41, the production management machine 2B of thisembodiment comprises a warp status judgment section 8A as a substitutefor the warp status inputting section (push buttons) 6B of thethirteenth embodiment. Two CCD cameras (imaging means) 7 are arranged atthe rearmost section of the corrugated-board fabrication machine 1.

As shown in FIG. 42, the CCD cameras 7 are arranged at the both ends ofthe width direction of a stacking section 192 of the stacker 19.Corrugated board sheets 25 formed by being cut by the cut-off device 18are transferred by a plurality of non-illustrated conveyors 191, andthen subsequently piled in the stacking section 192. The respective CCDcameras 7 photograph corrugated board sheets 25 from the respectivedifferent sides along the width direction thereof and output the imagedata to the warp status judgment section 8B.

The warp status judgment section 8B performs image processing on theimage data and measures the heights of the four corner points. Then, onthe basis of the differences of the measured heights, the warp statusjudgment section 8B judges a pattern of twist warp (twist warp A ortwist warp B) and an extent of warp (large, medium or small). The resultof the judgment is sent to the control variable calculating section 4B,which refers to the acquaintance database 3B based on the judgmentresult in order to respond to machine state information and to calculatea control variable of each particular control factor.

Here, the specific manner of judgment of warp status performed by thewarp status judgment section 8B will be described with reference toFIGS. 43 a and 43 b. As shown in FIG. 43 a, the CCD cameras 7 photographcorrugated board sheets 25 from the both sides of the width directionrespectively. Then the warp status judgment section 8B performs imageprocessing on image data from the CCD cameras 7 and calculates verticalvariation amounts a-d of the four corner points PA-PD of the corrugatedboard sheet 25 with respect to the reference line L0 shown in FIG. 43 b.

The warp status judgment section 8B calculates an amount TWF of twistwarp defined by the following formula (11) by using the verticalvariation amounts a-d. The warp pattern is determined by positivenessand negativeness of the warp amount TWF, and the warp height isdetermined by the largeness of the absolute value of the warp amountTWF. $\begin{matrix}{{TWF} = {\left\lbrack \frac{\left( {b - a} \right) + \left( {d - c} \right)}{2} \right\rbrack \times \frac{\alpha}{W \times L}}} & (11)\end{matrix}$where, W represents the length of the width of a corrugated board sheet25, L represents the length of the travel direction of a corrugatedboard sheet 25, and α is a constant used to make a warp amountdimentionless.

In the system for correcting possible warp of a corrugated board sheetaccording to this embodiment, twist warp of a corrugated board sheet 25is automatically corrected so that it is possible to accurately correcttwist warp of corrugated board sheets 25 with ease without depending onexperience and know-how of an operator. In the illustrated example, theusage of the acquaintance database 3B according to the ninth embodimentclassified a determined warp extent into large, medium and small. It ispossible for this system to determine a warp extent more sensitively sothat warp of a corrugated board sheet 25 can be corrected moreaccurately.

(C-6) Eighteenth Embodiment

FIG. 44 schematically shows the main part of a warp detection unitaccording to the present embodiment.

In the above seventeenth embodiment, the warp status judgment section 8Bdetects a warp status of a corrugated board sheet 25 on the basis ofimage data obtained by the CCD cameras 7. In the present embodiment, thetwo CCD cameras (imaging means) 7 are substituted by two variationsensors (variation amount detecting means) 7A and 7B, and the warpstatus judgment section 8B detects a warp status of a corrugated boardsheet on the basis of measurement data obtained by the variation sensors7A and 7B.

As shown in FIG. 44, the variation sensor 7A is slidably attached to arail 271 a, which horizontally extends along the width direction of acorrugated board sheet 25, through a variation sensor mounting member272 a. The variation sensor 7A includes non-illustrated driving meansand, within the above structure, is driven by the driving means so thatthe variation sensor 7A can horizontally moves along the width directionof a corrugated board sheet 25 and can be controlled to be positionedvertically over measurement points PC and PD respectively near the twoupstream corners of a corrugated board sheet 25 shown in FIG. 45. As aresult, it is thereby possible to obtain vertical variation amounts cand d between the variation sensor and each of the points PD and PC,respectively.

The other variation sensor 7B is, as shown in FIG. 44, slidably attachedto a rail 273 a, which is mounted to a frame 271 and which horizontallyextends along the width direction of a corrugated board sheet 25,through a variation sensor mounting member 274 a, which includesnon-illustrated driving means. The variation sensor 7B is driven by thedriving means and can horizontally moves in the width direction of acorrugated board sheet 25. As a result, the variation sensor 7B iscontrolled to be positioned vertically over measurement points PA and PBrespectively near the two downstream corners of a corrugated board sheet25 shown in FIG. 45 and can obtain vertical variations a and b betweenthe variation sensor and each of the points PA and PB, respectively.

The warp status judgment section 8B calculates an amount of twist warpby using the above formula (11).

The remaining configuration is identical to that of the seventeenthembodiment, so repetitious description is omitted here.

In order to detect twist warp, obtaining variation amounts in verticaldirection of the measurement points PA-PD near the four corners of acorrugated board sheet 25 is satisfactory. Alternatively, a variationsensor may be fixed to a position over each of the measurement pointsPA-PD.

In the present embodiment, the variation sensors detect variationamounts of the vertical direction of a corrugated board sheet 25 at thestacking section 192 of the stacker 19. Alternatively, it is sufficientthat a variation sensor obtains variation amounts in the verticalvariation of a corrugated board sheet the overall width of which hasbeen cut by the cut-off device 18 to serve as a final product. In otherwords, satisfactory detection is performed on a corrugated board sheet25 at any point downstream of the cut-off device 18. For example,variation sensors may be disposed on the conveyer 191 (see FIG. 44)arranged between the cut-off device 18 and the stacker 19, so that thedetection is performed on a corrugated board sheet 25 being transferredon the conveyer.

(C-7) Others

The thirteenth to the eighteenth embodiments have been described above.But the present invention should by no means be limited to thesethirteenth to eighteenth embodiments and various modifications andalteration can be suggested without departing from the gist of thepresent invention.

For example, the seventeenth embodiment shown in FIG. 41 includes thewarp status judgment section 8B and the CCD camera (imaging means) 7 assubstitute for the warp status inputting section (push buttons) 6B ofthe thirteenth embodiment shown in FIG. 30. The eighteenth embodimentshown in FIGS. 44 and 45 includes the warp status judgment section 8Band the variation sensors (variation amount detecting means) 7A and 7Bas substitute for the warp status inputting section (push buttons) 6B ofthe thirteenth embodiment. Alternatively, the fourteenth through thesixteenth embodiments may be modified so as to include the warp statusjudgment section 8B and the CCD camera (imaging means) 7 as substitutefor the warp status inputting section (push buttons) 6B or so as toinclude the warp status judgment section 8B and the variation sensors(variation amount detecting means) 7A and 7B as substitute for the warpstatus inputting section (push buttons) 6B.

The particular control factors should by no means be limited to thoseused in the foregoing embodiments, and another control factor thataffects a width-direction distribution of a tension of a single-face web22 or a top liner 23 can be used as a control factor to correct possiblewarp of a corrugated board sheet 25. The configurations of theacquaintance databases 3B described in the thirteenth and the fourteenthembodiment are therefore only examples and the acquaintance database 3can be set up in accordance with particular control factors that are tobe used. Also priority order thereof should by no means be limited tothose set in the foregoing embodiments and can be arbitrarily decided.

(D)

Hereinafter, systems for correcting possible warp of a corrugated boardsheet according to a nineteenth to a twenty-fifth embodiments andmodifications thereof of the present invention will now be describedwith reference to FIGS. 46-58. Parts and elements identical to thosedescribed in the foregoing embodiments are to be referred by the samereference numbers and description thereof will be partially omitted.

(D-1) Nineteenth Embodiment

FIG. 46 schematically shows a system for correcting possible warp of acorrugated board sheet according to the nineteenth embodiment, whichincludes a corrugated-board fabrication machine 1 and a productionmanagement machine 2C to manage the corrugated-board fabrication machine1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by a medium web preheater12 and then glue the medium web 21 to the bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat asingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13, a double facer 16 tofabricate a corrugated board (double-face web) 24 by gluing thesingle-face web 22 pasted by the glue machine 15 and the top liner 23heated by the top liner preheater 14, a slitter scorer 17 to slit andscore the corrugated board 24 fabricated by the double facer 16, acut-off device 18 to make a final product (a corrugated board sheet) 25by dividing a corrugated board 24 scored and subjected to anotherprocedure by the slitter scorer 17 into separated forms, and a stacker19 to sequentially stack corrugated board sheets in order offabrication.

Among these elements 10 to 19, an element that affects a moisturecontent of a bottom liner 20 and an element that affects a moisturecontent of a top liner 23 associate with (affect) warp of a corrugatedboard sheet 25 in the width direction. Here, the bottom liner preheater10, the single-face web preheater 13, the top liner preheater 14, thesingle facer 11, the glue machine 15 and the double facer 16 correspondto such elements.

As shown in FIG. 47, temperature sensors (moisture content measuringmeans) 240 a and 240 b are disposed at the entrance of a double facer 16(i.e., immediately upstream of the double facer 16) in such a posturethat the transfer path of a single-face web 22 or a top liner 23 isinterposed between the temperature sensors 240 a and 240 b. Thetemperature sensors 240 a and 240 b are respectively arranged so as toface to the center of the width direction of a single-face web 22 and atop liner 23, respectively in the illustrated example. The uppertemperature sensor 240 a detects a temperature Te1 of the bottom liner20, which temperature is the parameter associated with a moisturecontent of the upper surface (i.e., the bottom liner 20) of asingle-face web 22 immediately prior to being transferred into thedouble facer 16; and the lower temperature sensor 240 b detects atemperature Te2 of a top liner 23, which temperature is the parameterassociated with a moisture content of the top liner 23 immediately priorto being transferred into the double facer 16. As described below, awidth-direction warp status of a corrugated board sheet is detectedbased on these measured temperatures.

The production management machine 2C appropriately manages each ofelements 10, 11, 13-16 to correct warp of a corrugated board sheet 25.Focusing on a function for correcting warp of a corrugated board sheet25, the production management machine 2C includes an acquaintancedatabase 3C, a control variable calculating section 4C, the processcontroller 5C, and a warp status judgment section 8C, as shown in FIG.46.

The acquaintance database 3C retains setting values of control variables(adjustment variations from the current values) associated withparticular control factors affect the possible warp of a corrugatedboard sheet 25, which particular control factors are among controlfactors used to control the corrugated-board fabrication machine 1, orformulae used to determine the control variables that correlate withwarp status (a warp direction, a warp extent) of the corrugated boardsheet 25. Here, the particular control factors are control factors thataffect moisture contents of a bottom liner 20 or a top liner 23, andmore particularly are wrap amounts of the bottom liner 20 around theabove-described bottom liner heating rolls 101A and 101B and a wrapamount of the top liner 23 around the top liner heating roll 141.

For example, when a corrugated board sheet 25 has upward warp in thewidth direction (has a convex surface toward a top liner 23), a settingvalue or a formula of a control variable of each control factor isdefined in order to increase a moisture content of the top liner 23and/or decrease a moisture content of a bottom liner 20. Conversely,when a corrugated board sheet 25 has downward warp in the widthdirection (has a convex surface toward a bottom liner 20), a settingvalue or a formula of a control variable of each control factor isdefined in order to increase a moisture content of the bottom liner 20and/or decrease a moisture content of the top liner 23.

A setting value or a formula of a control variable of each controlfactor is defined in accordance with a predetermined priority order,that is, a priority order for outputs. For example, when a warp extentis small, only control variables with higher priorities are output; andwhen a warp extent is getting larger, other control variables areadditionally output in accordance with the priority order. In relationto the priority order, a control factor that more largely affects warp,i.e., a control factor that more largely contributes to warp correction,gets a higher priority.

A table in FIG. 48 shows the configuration of the acquaintance database3C according to the present embodiment. In the illustrated example, awarp status of a corrugated board sheet 25 is judged by the warp statusjudgment section 8C to be described later by selecting one from sevenwarp status types of large upward warp, medium upward warp, small upwardwarp, no warp, large downward warp, medium downward warp and smalldownward warp. For each of the warp state types, control factors thatare to be output are determined in accordance with a priority order. Inthis embodiment, control factors (particular control factors) that areset are a wrap amount around a single-face web preheater (a wrap amountof a single-face web 22 around the single-web heating roll 131), a wrapamount around a top liner preheater (a wrap amount of a top liner 23around the top liner heating roll 141), and a wrap amount around abottom liner preheater (a wrap amount of a bottom liner 20 around thebottom liner preheater 101); the warp amounts around the single-face webpreheater and around the top liner preheater are given the firstpriority in the priority order and the warp amount around the bottomliner preheater is given the third priority.

In FIG. 48, a control factor with a circle (∘) or a double circle (⊚) isan output when a corrugated board sheet is in a corresponding warpstatus. A circle and a double circle represent an amount of controlvariable (adjustment variation from the current value) and a doublecircle represents a larger control variable than a circle of the samecontrol factor. Accordingly in this embodiment, if a corrugated boardsheet 25 has small upward warp for example, only wrap amounts around thesingle-face web preheater and around the top liner preheater areadjusted; if a corrugated board sheet 25 has medium upward warp, onlywrap amounts around the single-face web preheater and around the topliner preheater are similarly adjusted and the amounts of theadjustments thereof are increased; and if a corrugated board sheet 25has large upward warp, a wrap amount around the bottom liner preheateris additionally adjusted. Specific setting values and formulae to derivethe setting values are determined by experiments and simulations.

Width-direction warp of a corrugated board sheet 25 is caused by adifference in moisture content between a bottom liner 20 and a top liner23, which are to be joined together with a medium web 21 interposed. Thewarp status judgment section 8C judges a status of warp in the widthdirection in relation to a corrugated board sheet 25 on the basis of atemperature Te1 of a bottom liner 20, which temperature is the parameterassociated with a moisture content of the bottom liner 20 and which isdetected by the temperature sensor 240 a, and a temperature of Te2 of atop liner 23, which temperature is the parameter associated with amoisture content of the top liner 23 and which is detected by thetemperature sensor 240 b.

The manner for judgment of a warp status by the warp status judgmentsection 8C is described with reference to FIG. 49. First of all, thewarp status judgment section 8C judges which one of the three levels ofhigh, normal and low the temperatures Te1 and Te2 of liners 20 and 23are respectively on. If the combination of a bottom-liner temperatureTe1 and a top-liner temperature Te2 is (high, high), (normal, normal) or(low, low), no temperature difference (i.e., no moisture contentdifference) exists between the bottom liner 20 and the top liner 23 andthe warp status judgment section 8C estimates and judges that acorrugated board sheet that is to be formed by joining the bottom liner20 and the top liner 23 together generates no warp. If the combinationof a bottom-liner temperature Te1 and a top-liner temperature Te2 is(high, high) or (low, low), the process controller 5C executes normalmatrix control that is to be described later such that a bottom-linertemperature Te1 and a top-liner temperature Te2 become normal.

The warp status judgment section 8C is set to estimate and judge that aresultant corrugated board sheet has downward warp (has a convex surfacetoward the bottom liner 20) if the upper bottom liner 20 is higher intemperature than the top liner 23, that is, the lower top liner 23 ishigher in moisture content than the bottom liner 20. The warp statusjudgment section 8C further estimates and judges the extent of the warpin accordance with the absolute value

T of the temperature difference between the liners 20 and 23. In otherwords, if a bottom-liner temperature Te1 is high and a top-linertemperature Te2 is normal, the resultant corrugated board sheet isestimated to have medium downward warp; if a bottom-liner temperatureTe1 is high and a top-liner temperature Te2 is low, the resultantcorrugated board sheet is judged to have large downward warp larger inextent than the above medium downward warp because of relatively hightemperature difference

T; and if a bottom-liner temperature Te1 is normal and a top-linertemperature Te2 is low, the resultant corrugated board sheet is judgedto have small downward warp that is smaller in extent than the abovemedium downward warp because of the low-side temperatures of both liners20 and 23.

On the other hand, if a lower top liner 23 is high in temperature than abottom liner 20, the warp status judgment section 8C estimates andjudges that a resultant corrugated board sheet has upward warp (has aconvex surface toward the top liner 23). If a top-liner temperature Te2is high and a bottom-liner temperature Te1 is normal, the resultantcorrugated board sheet is estimated to have medium upward warp; if atop-liner temperature Te2 is high and a bottom-liner temperature Te1 islow, the resultant corrugated board sheet is judged to have large upwardwarp larger in extent than the above medium upward warp because of hightemperature difference

T; and if a top-liner temperature Te2 is normal and a bottom-linertemperature Te1 is low, the resultant corrugated board sheet is judgedto have small upward warp that is smaller in extent than the abovemedium upward warp because of the high-side temperatures of both liners20 and 23.

On the basis of warp information from the warp status judgment section8C, the control variable calculating section 4C retrieves and reads asetting value or a setting formula of a control variable for eachcorresponding control factor from the acquaintance database 3C andcalculates each control variable associated with machine state(operating state) of the corrugated-board fabrication machine 1. Thecontrol variable calculating section 4C and the acquaintance database 3Cof this embodiment serve as the control factor selecting means and thecontrol variable calculating means of the present invention.

A machine state represents the current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of a web), a wrapamount of a web around each of the heating rolls 101A, 101B, 131 and141, vapor pressure applied to each of the heating rolls 101A, 101B, 131and 141, gap amounts between the rolls 116 b and 114 and between therolls 116 b and 116 c in the single facer 11, a gap amount between thepasting roll 151 b and the pressure bar 152 a in the glue machine 15,pressures applied by the pressure units 164 and vapor pressure appliedto the hotplates 162 in the double facer 16, and spray amounts of theshower units 161A and 161B. These values of the machine state is inputfrom the process controller 5C, which is to be described later.

When the warp status judgment section 8C estimates and judges no warp isgenerated on a corrugated board sheet, the control variable calculatingsection 4C instructs the process controller 5C to return all the controlfactors to the originals (values determined by matrix control based onproduction state information such as a base-board composition, a basisweight of the base board, the width of a corrugated board sheet, a fluteand the like).

The process controller 5C overall controls each of the elements 10-19that constitute of the corrugated-board fabrication machine 1. Theprocess controller 5C usually controls each of the elements 10-19 byperforming matrix control based on production state information.However, when the warp status judgment section 8C estimates and judgesthat warp is to be generated on a corrugated board sheet, the processcontroller 5C controls each of control factors (here, one or anarbitrary combination of a wrap amount around the single-web preheater13, a wrap amount around the top liner preheater 14, and a wrap amountaround the bottom liner preheater 10) using one or more controlvariables calculated in the control variable calculating section 4C.

Conversely, if the warp status judgment section 8C estimates and judgesno warp is to be generated on a corrugated board sheet, the processcontroller 5C controls the elements 10, 13 and 14 to return all thecontrol factors to the originals. The process controller 5C alwaysgrasps a current machine state of the corrugated-board fabricationmachine 1, and outputs the current machine state to the control variablecalculating section 4C periodically or in response to a request from thecontrol variable calculating section 4C. Namely, the process controller5C serves as the control means and the running-state informationobtaining means according to the present invention.

The flow diagram FIG. 50 describes a succession of procedural steps ofcorrecting warp of a corrugated board sheet 25 using the above-describedfunctions of the production management machine 2C.

First of all, the production management machine 2C checks a machinestate at step C10 and checks a production state at step C20. In theensuing step C30, the production management machine 2C obtainsinformation of temperatures of a bottom liner 20 and a top liner 23 viathe temperature sensors 240 a and 240 b. In the manner described above,the production management machine 2C estimates and judges a warp statusof the corrugated board sheet 25 based on the temperature information atstep C40 and further estimates and judges whether or nor the corrugatedboard sheet 25 is to have warp at the ensuing step C50. If thecorrugated board sheet 25 is judged to have warp, the procedural stepsproceed to step C60, so that one or more control factors (here, one or acombination of a wrap amount around the single-face web preheater, awrap amount around the top liner preheater, and a wrap amount of thebottom liner preheater) to be controlled are selected based on the warpstatus, considering the priority order.

In the subsequent step C70, the production management machine 2Ccalculates a control variable of each selected control factor in linewith machine state information obtained in the step C10 with referenceto the acquaintance database 3C. At this time, production managementmachine 2C may use the production state information obtained at step A20as reference data, for example, in order to change wrap amountsconsidering base paper composition (thick paper, thin paper) After that,the production management machine 2C outputs the calculated controlvariables to corresponding elements (here, one or a combination of thesingle-face web preheater 13, the top liner preheater 14, and the bottomliner preheater 10) at step C80.

On the other hand, if the corrugated board sheet 25 is judged to have nowarp at the step C50, the production management machine 2C carries outnormal matrix control.

According to the system for correcting a possible warp of a corrugatedboard sheet of the present embodiment, a warp status of a corrugatedboard sheet 25 is automatically judged and a wrap amount around thesingle-face web preheater, a wrap amount around the top liner preheaterand/or a wrap amount around the bottom liner preheater which amountsaffect warp of a corrugated board sheet 25 are adjusted by theproduction management machine 2C. Thereby, it is possible to accuratelyand automatically correct warp of corrugated board sheets with easewithout depending on experience and know-how of an operator.

When short-run fabrication of corrugated board sheets is performed (thespecification of corrugated board sheets to be fabricated is varied in ashort term), there is possibility that warp cannot be corrected byfeed-back control, in which a status of warp actually generated on acorrugated board sheet 25 is detected and the warp is corrected based onthe detected warp status, because liners 20 and 23 may have passedthrough elements (in this case, the single-face web preheater 13, thetop liner preheater 14, and the bottom liner preheater 10) that are ableto correct the warp before such feed-back control takes effect.Advantageously in this system for correcting possible warp, a warpstatus of a corrugated board sheet 25 is estimated and judged on thebasis of temperatures of liners 20 and 23 before being joined togetherand management for correct possible warp is carried out based on theresult of the determination and the judgment at an early stage so that awarp can be corrected even during short-run fabrication.

At that time, since the production management machine 2C successivelyadds selected control factors in accordance with a priority order,considering an extent of warp of a corrugated board sheet 25, the extentof adjustment for warp correction can be larger in accordance with thewarp extent so that warp correction of a corrugated board sheet 25 canbe accomplished rapidly. In particular in this embodiment, it ispossible to correct warp of a corrugated board sheet 25 faster byproviding a control factor that more largely affects the warp with ahigher priority.

In this nineteenth embodiment, the control factors to correct warp of acorrugated board sheet 25 are a wrap amount around the single-face webpreheater, a wrap amount around the top liner preheater and a wrapamount around the bottom liner preheater. These control factors are onlyone example and a greater number of control factors to be controlled maybe used likewise in the following second through twenty-thirdembodiments.

(D-2) Twentieth Embodiment

FIG. 51 shows the configuration of the acquaintance database 3Caccording to a twentieth embodiment of the present invention. Theelements except the acquaintance database 3C are identical to those ofthe nineteenth embodiment, so repetitious description will be omittedhere.

In this embodiment, the single facer 11 and the glue machine 15 are alsocontrolled in order to correct warp. An adhesive-gap amount of thesingle facer (a gap amount between the pasting roll 116 b and the upperroll 114 (or a gap amount between the pasting roll 116 b and the meterroll 116 c)) and an adhesive-gap amount of the glue machine (a gapamount between the pasting roll 151 b and the pressure bar 152 a) areset as particular control factors in addition to control factors of thenineteenth embodiment. In the same manner as the nineteenth embodiment,the wrap amounts around the single-face web preheater and around the topliner preheater are given the first priority in the priority order and awrap amount around the bottom liner preheater is given the thirdpriority. Meanwhile the adhesive-gap amount of the single facer and theadhesive-gap amount of the glue machine are given the fourth and thefifth priorities, respectively.

Since the system for correcting possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the nineteenth embodiment, it is possible to perform moresensitive control than the nineteenth embodiment so that warp of acorrugated board sheet 25 can be corrected more accurately.

(D-3) Twenty-First Embodiment

FIG. 52 shows the configuration of the acquaintance database 3Caccording to a twenty-first embodiment of the present invention. Theelements in this embodiment except the acquaintance database 3C are alsoidentical to those of the nineteenth embodiment, so repetitiousdescription will be omitted here.

In this embodiment, the double facer 16 is also controlled in order tocorrect warp. A pressure applied by the double facer (pressure appliedby the pressure units 164) and a rate of the double facer (a travel rateof a single-face web 22 and a top liner 23 in the double facer 16) areset as particular control factors in addition to control factors of thetwentieth embodiment. In the same manner as the twentieth embodiment,the wrap amounts around the single-face web preheater and around the topliner preheater are given the first priority in the priority order; thewrap amount around the bottom liner preheater is given the thirdpriority; the adhesive-gap amount of the single facer is given thefourth priority; and the adhesive-gap amount of the glue machine isgiven the fifth priority. Further, the pressure of the double facer andthe rate of the double facer are given the sixth and the seventhpriorities, respectively.

Since the system for correcting possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the twentieth embodiment, it is possible to perform moresensitive control than the twentieth embodiment so that warp of acorrugated board sheet 25 can be corrected more accurately.

(D-4) Twenty-Second Embodiment

FIG. 53 shows the configuration of the acquaintance database 3Caccording to a twenty-second embodiment of the present invention. Alsoin this embodiment, the elements except the acquaintance database 3C areidentical to those of the nineteenth embodiment, so repetitiousdescription will be omitted here.

In this embodiment, a vapor pressure in the double facer (a pressure ofvapor supplied to the hotplates 162) is added as a particular controlfactor to control factors of the twenty-first embodiment. In the samemanner as the twenty-first embodiment, the wrap amounts around thesingle-face web preheater and around the top liner preheater are giventhe first priority in the priority order; the wrap amount around thebottom liner preheater is given the third priority; the adhesive-gapamount of the single facer is given the fourth priority; and theadhesive-gap amount of the glue machine is given the fifth priority; andthe pressure of the double facer is given the sixth priority. Mean whilethe vapor pressure in double facer and the rate of the double facer aregiven the seventh and the eighth priorities, respectively.

Since the system for correcting a possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the twenty-first embodiment, it is possible to perform moresensitive control than the twenty-first embodiment so that warp of acorrugated board sheet 25 can be corrected more accurately.

(D-5) Twenty-Third Embodiment

FIG. 54 shows the configuration of the acquaintance database 3Caccording to a twenty-third embodiment of the present invention. Theelements except the acquaintance database 3C are also identical to thoseof the nineteenth embodiment, so repetitious description will be omittedhere.

In this embodiment, the shower units 161A and 161B are also controlledin order to correct warp. A spray amount onto the bottom liner side (anamount of spray from the shower unit 161A) and a spray amount onto thetop liner (an amount of spray from the shower unit 161B) are added asparticular control factors to the control factors of the twenty-secondembodiment. These spray amounts are given the first priority while thewrap amounts around the single-face web preheater and around the topliner preheater are given the second priority in the priority order; thewrap amount around the bottom liner preheater is given the fourthpriority; the adhesive-gap amount of the single facer is given the fifthpriority; and the adhesive-gap amount of the glue machine is given thesixth priority; the pressure of the double facer is given the seventhpriority; the vapor pressure in double facer is given the eighthpriority; and the rate of the double facer are given the ninth priority.

Since the system for correcting possible warp of a corrugated boardsheet according to this embodiment has a larger number of controlfactors than the twenty-second embodiment, it is possible to performmore sensitive control than the twenty-second embodiment so that warp ofa corrugated board sheet 25 can be corrected more accurately. The addedspray amounts with high correction capacities can contribute to furtherrapidly warp correction.

(D-6) Twenty-Fourth Embodiment

next, a twenty-fourth embodiment of the present invention will now bedescribed with reference to FIGS. 55 and 56. This embodiment is featuredby moisture content measuring means and the remaining configuration isidentical to that of the nineteenth embodiment. Any acquaintancedatabase 3C described in the first through twenty-third embodiments canbe used here.

In the system for correcting possible warp of a corrugated board sheetin this embodiment, the moisture content measuring means takes the formof moisture sensors 241 a and 241 b respectively arranged over and underthe transfer path of a single-face web 22 and a top liner 23 at theentrance of the double facer 16 as shown in FIG. 55 while the moisturecontent measuring means of each of the above embodiments takes the formof temperature sensors 240 a and 240 b. The moisture sensors 241 a and241 b respectively faces the centers of the width direction of liners 20and 23, respectively.

As shown in FIG. 56, the warp status judgment section 8C judges whichone of the three levels of high, normal and low the moisture content Mo1and Mo2 of a single-face web 22 and a top liner 23 are respectively onand estimates and judges warp of a resultant corrugated board sheet 25on the basis of the combination of these moisture content levels. Indetail, if the combination of a single-face-web moisture content Mo1 anda top-liner moisture content Mo2 is (high, high), (normal, normal) or(low, low), no difference in moisture content exists between thesingle-face web 22 and the top liner 23 and the warp status judgmentsection 8C estimates and judges that no warp is to be generated.

If the combination of moisture content Mo1 and moisture content Mo2 is(high, high) or (low, low), the process controller 5C executes normalmatrix control such that moisture contents of the single-face web andthe top liner become normal.

The warp status judgment section 8C is set to estimate and judge that aresultant corrugated board sheet generates upward warp if a bottom liner20 is higher in moisture content than a top liner 23: a normal moisturecontent Mo1 of a bottom liner 20 and a low moisture content Mo2 of a topliner 23 are judged to have medium upward warp; a high moisture contentMo1 of a bottom liner 20 and a low moisture content Mo2 of a top liner23 are judged to have large upward warp; and a high moisture content Mo1of a bottom liner 20 and a normal moisture content Mo2 of a top liner 23are judged to have small upward warp.

Conversely, the warp status judgment section 8C is set to estimate andjudge that a resultant corrugated board sheet generates downward warp ifa bottom liner 20 is lower in moisture content than a top liner 23: alow moisture content Mol of a bottom liner 20 and a normal moisturecontent Mo2 of a top liner 23 are judged to have medium downward warp; alow moisture content Mo1 of a bottom liner 20 and a high moisturecontent Mo2 of a top liner 23 are judged to generate large downwardwarp; and a normal moisture content Mo1 of a bottom liner 20 and a highmoisture content Mo2 of a top liner 23 are judged to generate smalldownward warp.

On the basis of warp information from the warp status judgment section8C, the control variable calculating section 4C retrieves and reads asetting value or a setting formulae of a control variable of eachcorresponding control factor from the acquaintance database 3C in thesame manner as the foregoing embodiments. The process controller 5C thencontrols the control factors using the control variables calculated bythe control variable calculating section 4C.

The remaining configuration is identical to those of the nineteenththrough twenty-third embodiments, so any repetitious description will beomitted here.

According to the system for correcting possible warp of a corrugatedboard sheet of the twenty-fourth embodiment, it is possible to correctwarp in the width direction of a corrugated board sheet 25 rapidly andalso possible to correct warp in the width direction during short-runfabrication.

(D-7) Twenty-Fifth Embodiment

A twenty-fifth embodiment of the present invention will now be describedwith reference to FIG. 57. This embodiment is featured by an arrangementof the moisture content measuring means and the remaining configurationis identical to that of the nineteenth embodiment. Any acquaintancedatabase 3C described in the nineteenth through twenty-third embodimentscan be used here.

While the temperature sensors 240 a and 240 b serving as the moisturecontent measuring means are disposed at the entrance of the double facer16 in the above nineteenth to twenty-third embodiment, the system forcorrecting possible warp of a corrugated board sheet in this embodimentplaces these temperature sensors 240 a and 240 b at the exit of thedouble facer 16 (i.e., immediate downstream of double facer 16).

Accordingly in the system for correcting possible warp of a corrugatedboard sheet of the twenty-fifth embodiment, comparing with feed-backcontrol of each control factor on the basis of warp status informationabout a corrugated board sheet 25 stacked in the stacker 19 for example,obtaining of warp status information is carried out further upstreamside in corrugated-board fabrication process. Whereupon warp correctioncan be accomplished at an early stage and this embodiment can deal withshort-run fabrication.

Alternatively, the moisture content sensors 241 a and 241 b, serving assubstitutes for temperature sensors 240 a and 240 b, may be arranged atthe exit of the double facer 16 as shown in FIG. 58. In this case, warpstatus is judged in accordance with moisture contents Mo1 and Mo2respectively of a single-face web 22 and a top liner 23 in the samemanner as the twenty-fourth embodiment shown in FIG. 56.

(D-8) Others

The above is the description of the nineteenth through the twenty-fifthembodiments of the present invention. But, the present invention shouldby no means be limited to the foregoing nineteenth to the twenty-fifthembodiments and various alternations and modifications can be suggestedwithout departing from the gist of the present invention.

For example, the above embodiments do not use vapor pressures applied toeach of the heating rolls 101, 131 and 141 as particular controlfactors; alternatively, it is, of course, possible to correct warp of acorrugated board sheet 25 by using these control factors. Further, otherthan the above example, any control factor that affects a moisturecontent of a bottom liner 20 or a top liner 23 can be used as aparticular control factor to correct a warp of a corrugated board sheet25. Accordingly, the configurations of the acquaintance databases 3C ofthe nineteenth through the twenty-fifth embodiments are only examplesand can be created in accordance with particular control factors thatare to be used. The priority orders in the acquaintance databases 3Cshould by no means be limited to the foregoing examples and can bearbitrary set.

In the foregoing nineteenth to twenty-fifth embodiments, the warp statusjudgment section 8C judges a warp extent on the three levels of large,medium and small. Alternatively, a warp extent may be classified intofurther detailed levels so that warp of a corrugated board sheet 25 canbe corrected more accurately.

The moisture content measuring means in each of the nineteenth throughthe twenty-fifth embodiment takes the form of temperature sensors ormoisture content sensors. Alternatively, a pair a temperature sensor anda moisture content sensor may be disposed for each of liners 20 and 23.In this case, a measurement value of one of a temperature sensor and amoisture content sensor may be used for judgment of a warp status and ameasurement value of the other sensor may be used as a reference thataffects the judgment; or measurement values of both of the temperaturesensor and the moisture content sensor may be used for judgment of awarp status.

In the above nineteenth through the twenty-fifth embodiments, themoisture content measurement means (a temperature sensor or a moisturecontent sensor) is placed in the center of the width direction of eachof liners 20 and 23 so as to measure a moisture content at the centerpoints of the liners 20 and 23 as representing values. Alternatively,the moisture content measurement means may measure moisture contents ofliners 20 and 23 along the width direction. Specifically, a plurality ofsensors serving as the moisture content measurement means are fixed inthe same height along the width of each of liners 20 and 23; or onesensor serving as the moisture content measurement means is movablyinstalled in the width direction so that a moisture content iscontinuously monitored. The averages of the measurement results may beused as representing values of moisture contents of liners 20 and 23.

With this configuration, even if a liner 20 or 23 has a moisture contentvaries in the width direction, it is possible to precisely judge a warpstatus.

(E)

Hereinafter, systems for correcting possible warp of a corrugated boardsheet according to twenty-sixth to twenty-ninth embodiments andmodifications thereof of the present invention with reference to FIGS.59-65. Parts and elements identical to those described in the foregoingembodiments are to be referred by the same reference numbers.

A corrugated board sheet fabricated by means of the present inventioncan ensure predetermined quality of particular aspects by automatedcontrol. An example manner to control to inhibit width-direction upwardor downward warp will be described in each of twenty-sixth totwenty-ninth embodiments.

(E-1) Twenty-Sixth Embodiment

FIG. 59 schematically shows a system for fabricating a corrugated boardsheet according to the twenty-sixth embodiment of the present invention.The system for fabricating a corrugated board sheet according to thetwenty-sixth embodiment includes a corrugated-board fabrication machine1 and a production management machine 2D to manage the corrugated-boardfabrication machine 1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by the medium web preheater12 and then glue the medium web 21 to the bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat thesingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13, a double facer 16 tofabricate a corrugated board 24 by gluing the single-face web 22 pastedby the glue machine 15 and the top liner 23 heated by the top linerpreheater 14, a slitter scorer 17 to slit and score the corrugated board24 fabricated by the double facer 16, a cut-off device 18 to make afinal product (a corrugated board sheet) 25 by dividing a corrugatedboard 24 scored and subjected to another procedure by the slitter scorer17 into separated forms, and a stacker 19 to sequentially stackcorrugated board sheets 25 in order of fabrication.

Among these elements 10 to 19, an element that affects a moisturecontent of a bottom liner 20 or an element that affects a moisturecontent of a top liner 23 associates with warp in the width direction ofa corrugated board sheet 25. Here, the bottom liner preheater 10, thesingle-face web preheater 13, the top liner preheater 14, the singlefacer 11, the glue machine 15 and the double facer 16 correspond to suchelements. Hereinafter, the configurations of these elements 10, 11,13-16 are shown in FIGS. 2-4, and have already been described in detailabove, so repetitious description is omitted here.

The production management machine 2D appropriately controls each of theelements 10, 11, and 13-16, and includes, as shown in FIG. 59, a controlvariable calculating section 4D, a process controller 5D, an optimumrunning-condition information memory 5Da, and a warp status OK button(quality information detecting means, quality information inputtingmeans) 5Db.

The control variable calculating section 4D has a function as theproduction-state information obtaining means of the present invention,and obtains production-state information from a non-illustrated uppersystem used for production management. The control variable calculatingsection 4D calculates each control variable on the basis of suchproduction state information and machine state information (runningstate) of the corrugated-board fabrication machine 1 obtained throughthe process controller 5D, and outputs the result of the calculation tothe process controller 5D. The process controller 5D controls eachcontrol variable in accordance with control instructions from thecontrol variable calculating section 4D. The control variablecalculating section 4D and the process controller 5D carry out matrixcontrol using production-state information and running-state informationin the above described manner.

The process controller 5D always grasps a current machine state of thecorrugated-board fabrication machine 1, and outputs the current machinestate to the control variable calculating section 4D regularly or inresponse to a request from the control variable calculating section 4D.Namely, the process controller 5D serves as the control means and therunning-state information obtaining means according to the presentinvention.

A machine state represents the current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of a web), a wrapamount of a web around each of the heating rolls 101A, 101B, 131 and141, a vapor pressure applied to each of the heating rolls 101A, 101B,131 and 141, gap amounts between the rolls 116 b and 114 and between therolls 116 b and 116 c in the single facer 11, a gap amount between thepasting roll 151 b and the pressure bar 152 a in the glue machine 15,pressures applied by the pressure units 164 and vapor pressured appliedto hotplates 162 in the double facer 16, spray amounts of the showerunits 161A and 161B, and so on.

In this system for fabricating a corrugated board sheet, a press of thewarp status OK button 5Db notifies the production management machine 2Dthat a corrugated board sheet has no warp in the width direction. Anoperator visually checks width-direction warp status of a corrugatedboard sheet being stacked in the stacker 19 or being transferred fromthe double facer 16 to the stacker 19, and, if the corrugated boardsheet has no warp, presses the warp status OK button 5Db.

As a consequence, production state information and running stateinformation concerning various issues at the time point of the press ofthe warp status OK button 5Db are output to the optimumrunning-condition information memory 5Da, which correlates theproduction-state information with the running-state information andretains these information pieces in the form of a data set. Namely, arunning state at the time of a press of the warp status OK button 5Da isstored as an optimum running state at the time of the correspondingproduction state.

At least one from issues that individually affect warp of a corrugatedboard sheet is selected as each of production state information andrunning state information, which are correlated with each other whenstored in the optimum running-condition information memory 5Da. Here,the width of a corrugated board sheet, a flute, the configuration andweight of a base paper are stored as production state information, andrunning state information to be stored are particular control factorsthat affect a moisture content of a bottom-liner 20 or a top-liner 23and width-direction warp of a corrugated board sheet which particularcontrol factors are a rate of the double facer (a travel rate of asingle-face web 22 and the top liner 23 in the double facer 16), a wrapamount of a single-face web around the single-face web preheater 13, awrap amount of a top liner around the top liner preheater 14, a wrapamount of a bottom liner around the bottom liner preheater 10, anadhesive-gap amount of the single facer (a gap amount between thepasting roll 116 b and the upper roll 114 (or a gap amount between thepasting roll 116 b and the meter roll 116 c)), an adhesive-gap amount ofthe glue machine (a gap amount between the pasting roll 151 b and thepressure bar 152 a), and a pressure of double facer (pressures appliedby the press units 164).

Since the process controller 5D always grasps each issue of productionstate information as described above, if a specification of corrugatedboard sheets is switched to another specification so that productionstate is to change, the process controller 5D retrieves a data sethaving a production state corresponding to the new specification (havingidentical width, flute, configuration and weight of base paper (here,including not only a specification perfectly identical but also aspecification substantially identical)) from the optimumrunning-condition information memory 5Da.

If a desired data set is found, the process controller 5D reads therunning state information, as the optimum running state, of the desireddata set and then controls each control factor such that the controlfactor corresponds to the read running state information. It can beconsidered that the optimum running-condition information memory 5Dateaches optimum running state information to the process controller 5Dand this control is therefore called teaching control hereinafter.

Conversely, if optimum running state information corresponding to thenew production state is not found in the optimum running-conditioninformation memory 5Da, the process controller 5D carries out normalmatrix control.

In the system for fabricating a corrugated board sheet according to thisembodiment, an operator visually judges a warp status of a corrugatedboard sheet 25 fabricated in the corrugated-board fabrication machine 1,and presses the warp status OK button 5Db if the corrugated board sheet25 has no warp. The pressing the warp status ok button 5Dd stores therunning state at that time as the optimum running state corresponding tothe current production state and, subsequently, when fabrication on thesame production state is to be carried out, execution of teachingcontrol can automatically adjust a rate of the double facer, a wrapamount around the single-face web preheater 13, a wrap amount around thetop liner preheater 14, a wrap amount around the bottom liner preheater10, an adhesive-gap amount of the single facer, an adhesive-gap amountof the glue machine, and a pressure of double facer to those in theoptimum running state. Thereby, it is possible to accurately correctwarp of corrugated board sheets with ease without depending onexperience and know-how of an operator.

When short-run fabrication of corrugated board sheets is performed (thespecification of corrugated board sheets to be fabricated is varied inthe short term), there is a possibility that warp cannot be corrected byfeed-back control, in which a status of warp actually generated on acorrugated board sheet 25 is detected and the warp is corrected based onthe detected warp status, because liners 20 and 23 being subjected toshort-run fabrication pass through elements (in this case, thesingle-face web preheater 13, the top liner preheater 14, and the bottomliner preheater 10) that are able to correct the warp before suchfeed-back control takes effect. Advantageously in this system forcorrecting possible warp, even when short-run fabrication takes place,since particular control factors are adjusted so as to be in thecorresponding optimum running state at the same time as switching ofproduction state, warp can be inhibited.

(E-2) Twenty-Seventh Embodiment

FIG. 60 shows a system for fabricating a corrugated board sheetaccording to a twenty-seventh embodiment of the present invention.

The system for fabricating a corrugated board sheet of this embodimentincludes, as shown in FIG. 60, a warp elimination support system formedby an acquaintance database 3D and a warp status inputting section 6D inaddition to the elements of the system for fabricating a corrugatedboard sheet according to the twenty-sixth embodiment described abovewith reference to FIG. 59. In other words, the production managementmachine 2D of this embodiment comprises an acquaintance database 3D,control variable calculating section 4D, a process controller 5D, anoptimum running-condition information memory 5Da, a warp status OKbutton 5Db and the warp status inputting section 6D.

The acquaintance database 3D retains setting values of control variables(adjustment variations from the current values) associated with one ormore particular control factors that affect the possible width-directionwarp of a corrugated board sheet 25 which particular control factors areamong control factors used to control the corrugated-board fabricationmachine 1, or formulae used to determine the control variables thatcorrelate with warp status (a warp direction, a warp extent) of thecorrugated board sheet 25.

For example, when a corrugated board sheet 25 has upward warp in thewidth direction (has a convex surface toward a top liner 23), a settingvalue or a formula of each control variable is determined in order toincrease a moisture content of the top liner 23 and/or decrease amoisture content of a bottom liner 20. Conversely, when a corrugatedboard sheet 25 has downward warp in the width direction (has a convexsurface toward the bottom liner 20), a setting value or a formula ofeach control variable is determined in order to increase a moisturecontent of the bottom liner 20 and/or decrease the moisture content of atop liner 23.

A setting value or a formula of each control variable is defined inaccordance with a predetermined priority order, which is a priorityorder for outputs. For example, when a warp extent is small, onlycontrol variables with higher priorities are output; and when a warpextent is getting larger, other control variables are additionallyoutput in accordance with the priority order. In relation to thepriority order, a control factor that more largely affects warp, i.e., acontrol factor that more largely contributes to warp correction, gets ahigher priority.

A table in FIG. 61 shows the configuration of the acquaintance database3D according to the present embodiment. In the illustrated example, awarp status of a corrugated board sheet 25 is classified into six typesof large upward warp, medium upward warp, small upward warp, largedownward warp, medium downward warp and small downward warp are setcorresponding to the number of push buttons as described later. For eachof the warp state types, control variables that are to be output aredefined in accordance with a priority order. In the illustratedembodiment, control factors (particular control factors) that are setare a wrap amount around the single-face web preheater (a wrap amount ofa single-face web 22 around the single-web heating roll 131), a wrapamount around the top liner preheater (a wrap amount of a top liner 23around the top liner heating roll 141), and a wrap amount around thebottom liner preheater (a wrap amount of a bottom liner 20 around thebottom liner preheater 101); the wrap amounts around the single-face webpreheater and around the top liner preheater are given the firstpriority in the priority order, and the wrap amount around the bottomliner preheater is given the third priority.

In FIG. 61, a control factor with a circle (∘) or a double circle (⊚) isan output when a corrugated board sheet is in a corresponding warpstatus. A circle and a double circle represent amounts of controlvariable (adjustment variations from the current values) and a doublecircle represents a larger control variable than a circle of the samecontrol factor. Accordingly in this embodiment, if a corrugated boardsheet 25 has small upward warp for example, only wrap amounts around thesingle-face web preheater and around the top liner preheater areadjusted; if corrugated board sheet 25 has medium upward warp, only wrapamounts around the single-face web preheater and around the top linerpreheater are similarly adjusted and the amounts of the adjustmentsthereof are increased; and if a corrugated board sheet 25 has a largeupward warp, a wrap amount around the bottom liner preheater isadditionally adjusted. Specific setting values and formulae to derivethe setting values are determined by experiments and simulations.

In this embodiment, a warp status of a corrugated board sheet 25 ismanually input to the warp status inputting section (warp statusinformation obtaining means) 6D by an operator. The warp statusinputting section 6D includes six push buttons 61 (large upward warp),62 (medium upward warp), 63 (small upward warp), 65 (large downwardwarp), 66 (medium downward warp) and 67 (small downward warp), each ofwhich associates with a warp status classified by the acquaintancedatabase 3D, and a reset button 64. Operator's depressing of acorresponding button inputs a selection signal to the control variablecalculating section 4D. A warp status of a corrugated board sheet 25 isjudged by an operator as a result of visual observation of thecorrugated board sheet 25 stacked in the stacker 19.

The control variable calculating section 4D retrieves and reads asetting variable or a formula to deriver the variable of eachcorresponding control factor from the acquaintance database 3D on thebasis of the selection signal received from the warp status inputtingsection 6D, and calculates each control variables associated with amachine state (a running state) of the corrugated-board fabricationmachine 1. In the illustrated embodiment, the control variablecalculating section 4D and the acquaintance database 3D include thecontrol factor selecting means of the present invention.

When the reset button 64 is selected in the warp status inputtingsection 6D, the control variable calculating section 4D instructs theprocess controller 5D to return all the control factors to the originals(values determined by matrix control based on production stateinformation such as a base-board composition, a basis weight of the baseboard, the width of a corrugated board sheet, a flute and the like) Theprocess controller 5D overall controls each of the elements 10-19 thatconstitute the corrugated-board fabrication machine 1. The processcontroller 5D usually controls each of elements 10-19 by performingmatrix control based on production state information if the processcontroller 5D does not store an optimum running state corresponding tothe current production state. However, when one from the push buttons61-63 and 65-57 is depressed in the warp status inputting section 6D,the process controller 5D controls each of control factors (here, one oran arbitrary combination of a wrap amount around the single-webpreheater 13, a wrap amount around the top liner preheater 14, and awrap amount around the bottom liner preheater 10) using one or morecontrol variables calculated in the control variable calculating section4D. When the reset button 64 is depressed, the process controller 5controls elements 10, 13, and 14 to return all the control factors tothe originals.

As described above, the system of this embodiment includes an optimumrunning-condition information memory 5Da and a warp status OK button 5Dbsimilarly to the twenty-sixth embodiment. An operator visually confirms,at a position downstream of the double facer, that a corrugated boardsheet has no warp, and presses the warp status OK button 5Db. As aresult, a running state at the time of the press is stored as an optimumrunning state at the time of the concurrent production state.

Then, when a specification of corrugated board sheets to be fabricatedhas been changed, the process controller 5D retrieves an optimum runningstate corresponding to the new current production state in the optimumrunning-condition information memory 5Da. If the corresponding optimumrunning state is found, the process controller 5D executes teachingcontrol in order to preferentially adjust predetermined particularcontrol factors (especially here, same as the twenty-sixth embodiment, arate of the double facer, a wrap amount of a single-face web around thesingle-face web preheater 13, a wrap amount of a top liner around thetop liner preheater 14, a wrap amount of a bottom liner around thebottom liner preheater 10, an adhesive-gap amount of the single facer,an adhesive-gap amount of the glue machine, and a pressure of the doublefacer) so as to become the corresponding optimum running state.

The flow diagram FIG. 62 describes a succession of procedural steps ofcorrecting warp of a corrugated board sheet 25 using the above-describedfunctions of the production management machine 2D.

First of all, the production management machine 2D checks a machinestate at step D10 and checks a production state at step D20. In theensuing step D25, the production management machine 2D retrieves anoptimum running state corresponding to the current production statechecked in step D20 in the optimum running-condition information memory5Da. If the corresponding optimum running state is stored, theprocedural steps proceed to step D27 to execute teaching control while,if the corresponding state is not stored, the procedural state proceedsto step D30.

At step D30, the production management machine 2D determines whether ornot a warp status can be currently input (i.e., one from the push button61-67 can be input). The determination is performed so as not to correctwarp while another trouble arises because warp correction is uselesswhen such another problem, e.g., a low rate of web travel due to anexcessive strong adhesive of glue, arises.

If a warp status can be input at step D30, the production managementmachine 2D determines whether or not a warp status has been actuallyinput at step D40. If a warp status has been input, the productionmanagement machine 2 selects one or more control factors (here, one oran arbitrary combination of a wrap amount around the single-face webpreheater, a wrap amount around the top liner preheater, and a wrapamount of the bottom liner preheater) in accordance with a priorityorder of the input warp status, i.e., the selected one of the pushbuttons 61-63 and 65-67 at step D50. Conversely, if judgment in step D40determines that a warp status has not been input, the procedural stepsproceed to step D45 to carry out matrix control.

In succession at step D60, the production management machine 2D refersto the acquaintance database 3D and calculates one or more controlvariables corresponding to the machine state obtained in step D10. Atthis time, production management machine 2D may use the production stateinformation obtained at step D20 as reference data in order to, forexample, change wrap amounts considering base paper composition (thickpaper, thin paper). The production management machine 2D outputs thecalculated control variables to corresponding elements (here, one or anarbitrary combination of the single-face web preheater 13, the top linerpreheater 14, and the bottom liner preheater 10) at step D70.

According to the system for correcting possible warp of a corrugatedboard sheet of the present embodiment, even if the optimumrunning-condition information memory 5Da does not retain an optimumrunning state corresponding to the current production state, a wrapamount around the single-face web preheater, a wrap amount around thetop liner preheater and a wrap amount around the bottom liner preheaterwhich amounts affect warp of a corrugated board sheet 25 areautomatically adjusted by the production management machine 2D by anoperator visually judging a warp status of a corrugated board sheet 25fabricated in the corrugated-board fabrication machine land simplydepressing one of buttons 61-63 and 65-67, the one corresponding to awarp status. Thereby, it is possible to accurately correct warp ofcorrugated board sheets with ease without depending on experience andknow-how of an operator.

At that time, since the production management machine 2D successivelyadds control factors in accordance with a priority order, considering anextent of warp of a corrugated board sheet 25, the extent of adjustmentfor warp correction can be larger in accordance with a warp extent sothat warp correction of a corrugated board sheet 25 can be accomplishedrapidly. In particular in this embodiment, it is possible to correctwarp of a corrugated board sheet 25 faster by providing a control factorthat more largely affects the warp with a higher priority.

In the illustrated embodiment, the control factors to correct warp of acorrugated board sheet 25 are a wrap amount around the single-face webpreheater, a wrap amount around the top liner preheater and a wrapamount around the bottom liner preheater. These control factors are onlyone example and a greater number of control factors to be controlledmaybe used. Control factors able to be added are exemplified by anadhesive-gap amount of the single facer, an adhesive-gap amount of theglue machine, a pressure of the double facer, a rate of the doublefacer, a vapor pressure of a double facer, a spray amount of the bottomliner side, and a spray amount of the top liner side.

(E-3) Twenty-Eighth Embodiment

Next, a twenty-eighth embodiment of the present invention will now bedescribed with reference to FIGS. 63, 12, 13 a and 13 b. The presentembodiment is featured by means for obtaining data in relation to a warpstatus of a corrugated board sheet 25 and the remaining configuration isidentical to that of the twenty-seventh embodiment shown in FIG. 60.

As shown in FIG. 63, the production management machine 2D of thetwenty-eighth embodiment includes a warp status judgment section(detection means) 8D as a substitution for the warp status inputtingsection (push buttons) 6D of the twenty-seventh embodiment. A CCD camera(imaging means) 7 is disposed at the rearmost section in thecorrugated-board fabrication machine 1.

The CCD camera 7 is arranged at a stacking section 192 of the stacker19. Corrugated board sheets 25 that have been cut by the cut-off device18 are transferred by a plurality of conveyors 191 and then subsequentlypiled in the stacking section 192. The CCD camera 7 images thewidth-direction side of corrugated board sheets 25 piled in the stackingsection 192 and outputs the obtained image data to the warp statusjudgment section 8D.

The warp status judgment section 8D performs image processing on theimage data from the CCD camera 7 and measures the heights ofpredetermined three points (on the both ends and the center) arranged inthe width direction. Then the warp status judgment section 8D judges awrap direction (upward or downward) in the width direction and a heightextent (large, medium or small) on the basis of the variance of themeasured heights. The result of the judgment is sent to the controlvariable calculating section 4D, which then selects one or more controlfactors based of the received result and calculates control variables ofthe selected control factors corresponding to machine state informationwith reference to the acquaintance database 3D.

Here, the judgment of a warp status by the warp status judgment section8D will now be specifically described with reference to FIGS. 13 a and13 b. The CCD camera 7 photographs a side of a corrugated board sheet 25across the width thereof as shown in FIG. 13 a. The warp status judgmentsection 8D performs image processing on image data from the CCD camera 7and calculates vertical variations a, b and p of predetermined threepoints (the driving-side corner PA, the operating-side corner OB and theweb center PP) arranged in the width direction with respect to thereference line LO.

The warp status judgment section 8D calculates vertical curl-up amountsA1 and C1 of the corners PB and PP with respect to a flat floor,assuming that a corrugated board sheet 25 is placed on the flat floor,on the basis of the vertical variation a, b and p using the followingformulae (A-1) and (A-2). Further, the warp status judgment section 8Dcalculates an amount WF_(CD) of warp in the width direction defined interms of the formula below (A-3) using the vertical curl-up amounts A1and C1. The warp direction is determined by positiveness andnegativeness of the warp amount WF_(CD), and the warp height isdetermined by the largeness of the absolute value of the warp amountWF_(CD). $\begin{matrix}{{A\quad 1} = {p - a}} & \left( {A\text{-}1} \right) \\{{B\quad 1} = {p - b}} & \left( {A\text{-}2} \right) \\{{{WF}_{CD}\left( {{A\quad 1},{B\quad 1}} \right)} = {\frac{\left( {{A\quad 1} + {B\quad 1}} \right)}{2} \times \frac{\alpha}{W^{2}}}} & \left( {A\text{-}3} \right)\end{matrix}$

-   -   where, W represents the length of the width of a corrugated        board sheet 25, and α is a constant used to make a warp amount        dimentionless.

In the a corrugated-board sheet fabrication system according to thisembodiment, warp of a corrugated board sheet 25 is automaticallycorrected so that it is possible to further accurately correct warp ofcorrugated board sheets with ease without depending on experience andknow-how of an operator. The illustrated example classifies a judgedwarp extent into three levels of large, medium and small. It is possiblefor this system to determine a warp extent more sensitively so that warpof a corrugated board sheet 25 can be corrected more accurately.

In this embodiment, the warp status judgment section 8D detects a warpstatus of a corrugated board sheet on the basis of image data obtainedby the CCD camera 7. Alternatively, the CCD camera (imaging means) 7 maybe replaced with a variation sensor (variation amount detecting means)7A shown in FIG. 15 a-15 c so that the warp status judgment section 8Ddetects a warp status of a corrugated board sheet based on a measurementresult of the variation sensor 7A.

Specifically, in the example shown in FIGS. 15 a and 15 b, the variationsensor 7A is slidably attached to a rail 71 a, which is fixed to a frame71 and which extends horizontally along the width direction of acorrugated board sheet 25, being interposed by a variation sensormounting member 72 a. Further, non-illustrated driving means isinstalled in the variation sensor mounting member 72 a and the variationsensor 7A is driven by the driving means so that the variation sensor 7Ais controlled to be positioned over the points of an operating-side edgePR, a driving-side edge PS and a sheet center PT. As a result, it isthereby possible to obtain vertical variation amounts s, t and r betweenthe lens surface of the variation sensor and each point of PR, PS andPT, as shown in FIG. 15 c.

The warp status judgment section 8D calculates vertical curl-up amountsA1 and C1 of edges PR and PS of a corrugated board sheet 25 with respectto a flat floor using the following formulae (A-4) and (A-5) and awidth-direction warp amount WF_(CD) is obtained by the above formula(A-3).A 1=t−s  (A-4)B 1=t−r  (A-5)

With this configuration, no warp judgment by the warp status judgmentsection 8D may automatically store the running state at that time as anoptimum running state associated with the current production state. Inthis case, the warp status OK button 5Db is dispensable, and the warpstatus judgment section 8D and the CCD camera(imaging means) 7 (or thevariation sensor (variation amount detecting means 7A)) serve as thequality information detecting means of the present invention.

(E-4) Twenty-Ninth Embodiment

Next, a twenty-ninth embodiment of the present invention will now bedescribed with reference to FIGS. 64 and 65. This embodiment is,differently from the above twenty-eighth embodiment, featured by meansto obtain information about warp of a corrugated board sheet and usesmeans for measuring moisture contents of liners 20 and 23, as substitutefor a CCD camera (imaging means) 7 or a variation sensor (variationamount detecting means) 7A. The remaining configuration is identical tothat of the twenty-eighth embodiment.

As shown in FIG. 64, the production management machine 2D of thisembodiment disposes, as moisture content measuring means, a temperaturesensor 240 a to measure a temperature Te1 of a bottom liner 20 whichtemperature is the parameters correlated with a moisture content of thebottom liner 20 and a temperature sensor 240 b to measure a temperatureTe2 of a top liner 23 which temperature is the parameters correlatedwith a moisture content of the top liner 23 at the entrance of thedouble facer 16. The temperature sensors 240 a and 240 b arerespectively arranged so as to face to the center in the width directionof a single-face web 22 and a top liner 23, respectively. The warpstatus judgment section 8D judges width-direction warp status of acorrugated board sheet 25 based on the temperatures Te1 and Te2 ofliners 20 and 23.

The manner for judgment of a warp status performed by the warp statusjudgment section 8D is described in detail with reference to FIG. 65.First of all, the warp status judgment section 8D judges which one ofthe three levels of high, normal and low the temperatures Te1 and Te2 ofliners 20 and 23 are respectively on. If the combination of abottom-liner temperature Te1 and a top-liner temperature Te2 is (high,high), (normal, normal) or (low, low), no temperature difference, i.e.,no moisture content difference, exists between the bottom liner 20 andthe top liner 23 and the warp status judgment section 8D estimates andjudges that a resultant corrugated board sheet that is to be formed bygluing the bottom liner 20 and the top liner 23 together generates nowarp.

If the combination of a bottom-liner temperature Te1 and a top-linertemperature Te2 is (high, high) or (low, low), matrix control isexecuted such that both bottom-liner temperature Te1 and top-linertemperature Te2 become normal.

The warp status judgment section 8D is set to estimate and judge that aresultant corrugated board sheet generates downward warp (has a convexsurface toward a bottom liner 20) if the upper bottom liner 20 is higherin temperature than a top liner 23, that is the lower top liner 23 ishigher in moisture content than the bottom liner 20. The warp statusjudgment section 8D additionally estimates and judges the extent of thewarp in accordance with the absolute value

T of the temperature difference between the liners 20 and 23 or thelike. In other words, if a bottom-liner temperature Te1 is high and atop-liner temperature Te2 is normal, the resultant corrugated boardsheet is estimated to have medium downward warp; if a bottom-linertemperature Te1 is high and a top-liner temperature Te2 is low, theresultant corrugated board sheet is judged to have large downward warplarger in extent than the above medium downward warp because ofrelatively large temperature difference

T; and if a bottom-liner temperature Te1 is normal and a top-linertemperature Te2 is low, the resultant corrugated board sheet is judgedto have small downward warp that is smaller in extent than the abovemedium downward warp because of the low-side temperatures of both liners20 and 23.

On the other hand, if the lower top liner 23 is high in temperature thanthe bottom liner 20, the warp status judgment section 8D estimates anddetermines that the resultant corrugated board sheet generates upwardwarp (has a convex surface toward a top liner 23). If a top-linertemperature Te2 is high and a bottom-liner temperature Tel is normal,the resultant corrugated board sheet is estimated to have medium upwardwarp; if a top-liner temperature Te2 is high and a bottom-linertemperature Te1 is low, the resultant corrugated board sheet is judgedto have large upward warp larger in extent than the above medium upwardwarp because of larger temperature difference

T; and if a top-liner temperature Te2 is normal and a bottom-linertemperature Tel is low, the resultant corrugated board sheet is judgedto have small upward warp that is smaller in extent than the abovemedium upward warp because of the low-side temperatures of both liners20 and 23.

Alternatively, the temperature sensors 240 a and 240 b maybe disposed atthe exit of the double facer, as substituted for the entrance thereof.

With the above-described configuration of the system for fabricating acorrugated board sheet according to the twenty-ninth embodiment,especially when the temperature sensors 240 a and 240 b are placed atthe entrance of the double facer, a warp status of a corrugated boardsheet 25 is estimated and judged on the basis of temperatures of liners20 and 23 before being glued together. Whereupon warp correction can beaccomplished at an early stage and this embodiment can deal withshort-run fabrication to inhibit warp even if an optimum running statecorresponding to the current production state is not stored in theoptimum running-condition information memory 5Da.

The moisture content measuring means may take the form of moisturesensors directly measure moisture content of liners 20 and 23, assubstituted for the temperature sensors 240 a and 240 b, and the warpstatus judgment section 8D estimates and judges warp of a corrugatedboard sheet 25 based on measurement result obtained by the moisturesensors.

(E-5) Others

The above is the description of the twenty-sixth through thetwenty-ninth embodiments of the present invention. But, the presentinvention should by no means be limited to the foregoing twenty-sixththrough the twenty-ninth embodiments and various alternatives andmodifications can be suggested without departing from the gist of thepresent invention.

For example, the twenty-sixth through the twenty-ninth embodiments ofthe present embodiment are applied to inhibition of warp of a corrugatedboard sheet, but, may alternatively be applied to inhibition of inferiorgluing of a corrugated board sheet. Specifically, an operator monitors agluing status of a corrugated board sheet 25 and, if no inferior gluingis observed, inputs the status from quality information inputting means(for example, in the form of a push button). In this case, as aparticular control factor affects a gluing state, at least one ofcontrol factors of an adhesive amount applied to a medium web at thesingle facer and an adhesive amount applied to a single-face web in theglue machine should be stored in the optimum running-conditioninformation memory 5Da.

(F)

Hereinafter, a system for correcting possible warp of a corrugated boardsheet according to the thirtieth embodiment and a modification thereofwill now be described with reference to FIGS. 66-69. Parts and elementsidentical to those described in the foregoing embodiments are to bereferred by the same reference numbers.

(F-1) Thirtieth Embodiment

FIG. 66 schematically shows a system for fabricating a corrugated boardsheet according to the thirtieth embodiment of the present invention.The system for fabricating a corrugated board sheet of this embodimentcomprises a corrugated-board fabrication machine 1 and a productionmanagement machine 2E to manage the corrugated-board fabrication machine1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by the medium web preheater12 and then glue the medium web 21 to the bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat asingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13, a double facer 16 tofabricate a corrugated board 24 by gluing the single-face web 22 pastedby the glue machine 15 and the top liner b 23 heated by the top linerpreheater 14, a slitter scorer 17 to slit and score the corrugated board24 fabricated by the double facer 16, a cut-off device 18 to make afinal product (a corrugated board sheet) 25 by dividing a corrugatedboard 24 scored and subjected to another procedure by the slitter scorer17 into separated forms, and a stacker 19 to sequentially stackcorrugated board sheets in order of fabrication.

The elements 10, 11, 13-16 are shown in FIGS. 2-4, and have been alreadydescribed in detail above, so repetitious description is omitted here.

The production management machine 2E appropriately controls each of theelements 10, 11, and 13-16, and includes, as shown in FIG. 66, a controlvariable calculating section 4E, a process controller 5E and a warpstatus judgment section (warp detection apparatus) 8E. Variation sensors(variation amount detecting means) 7A and 7B are arranged at therearmost section of the corrugated-board fabrication machine 1. Thevariation sensors 7A and 7B and the warp status judgment section 8E areincluded in an apparatus for automatically detecting type and extent ofwarp of a corrugated board sheet.

The control variable calculating section 4E obtains production-stateinformation from a non-illustrated upper system for productionmanagement. The control variable calculating section 4E calculates eachcontrol variable on the basis of such production state information andmachine state information (running state) obtained through the processcontroller 5E, and outputs the result of the calculation to the processcontroller 5E. The process controller 5E controls each control factor inaccordance with control instructions from the control variablecalculating section 4E. The control variable calculating section 4E andthe process controller 5E carry out matrix control usingproduction-state information and running-state information in the abovedescribed manner.

The process controller 5E always grasps a current machine state of thecorrugated-board fabrication machine 1, and outputs the current machinestate to the control variable calculating section 4E regularly or inresponse to a request from the control variable calculating section 4E.

A machine state represents the current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of a web), a wrapamount of a web around each of the heating rolls 101A, 101B, 131 and141, a vapor pressure applied to each of the heating rolls 101A, 101B,131 and 141, gap amounts between the rolls 116 b and 114 and between therolls 116 b and 116 c in the single facer 11, a gap amount between thepasting roll 151 b and the pressure bar 152 a in the glue machine 15,pressure applied by the pressure units 164 and vapor pressure applied tohotplates 162 in the double facer 16, spray amounts of the shower units161A and 161B and so on.

As shown in FIG. 27, the variation sensors 7A and 7B are respectivelyfixed to an upper rail 171 of the stacking section 192 in the stacker19; the variation sensor 7A measures a variation of the upstream side ofa corrugated board sheet 25 stacked in the stacking section 192 and thevariation sensor 7B measures a variation of the downstream side of thecorrugated board sheet 25 in the same manner as the twenty-seventhembodiment. Corrugated board sheets 25 cut by the cut-off device 18 aretransferred, by a plurality of conveyers 191, to and sequentiallystacked in the stacking section 192.

The variation sensor 7A is slidably attached to the rail 171 a, whichextends horizontally along the width direction of a corrugated boardsheet 25, through a variation sensor mounting member 172 a, the rail 171a being attached to the upper frame 171 at the stacking section 192through a variation sensor mounting member 172 b so as to slide along arail 171 b that horizontally extends in the travel direction of acorrugated board sheet 25.

Non-illustrated driving means is attached to the variation sensormounting members 172 a and 172 b. The variation sensor 7A is driven bythe driving means so that the variation sensor 7A can horizontally movein the width and the travel directions of a corrugated board sheet 25.Thereby, the variation sensor 7A is controled to be positionedvertically over a measurement point PD at the upstream corner on thedriving side of a corrugated board sheet 25, a measurement point PQ atthe upstream center in the width direction, a measurement point PC atthe upstream corner of the operating side, a measurement point PS at thecenter of the operating-side end in the travel direction and ameasurement point PR at the center of the driving-side edge in thetravel direction respectively shown in FIG. 67. It is possible to obtainvertical variation amounts c, d, q, r, and s of the points PC, PD, PQ,PR and PS, respectively, with respect to the variation sensor.

Meanwhile, as shown in FIG. 27, the variation sensor 7B is slidablyattached to a rail 173 a, which is attached to a frame 171 and whichhorizontally extends along the width direction of a corrugated boardsheet 25, through a variation sensor mounting member 174 a, whichincludes non-illustrated driving means. The variation sensor 7B isdriven by this driving means so as to horizontally move in the widthdirection of a corrugated board sheet 25. Thereby, the variation sensor7B is controlled to be positioned vertically over a measurement point PAat the downstream corner on the driving side of a corrugated board sheet25, a measurement point PPat the center of downstream end in the widthdirection and a measurement point PB the downstream corner on theoperating side of the corrugated board sheet 25, as shown in FIG. 67. Itis possible to obtain vertical variation amounts a, b and p of therespective points PA, PB and PP with respect to the variation sensor.

The corner points PA-PD do not necessarily have to be exactly at thefour corners of a corrugated board sheet 25 and points PA-PD near thefour corners are adequate. The measurement points PP-PS may be near tothe center points (being equidistant from the neighboring two corners)of the four sides of the corrugated board sheet 25.

Then the warp status judgment section 8E obtains a warp amount WF_(CD)in the width direction based on the difference of the vertical variationamounts of both ends of a sheet in the width direction with respect tothe center in the width direction. Here, the warp status judgmentsection 8E calculates a warp amount WF_(CD) in the width direction of acorrugated board sheet 25 as shown in the formula (B-1). That is, thewarp status judgment section 8E regards the vertical variation amount pof point PP at the center of the downstream side in the width directionas a reference to obtain a warp amount of the downstream side in thewidth direction. Then, the warp status judgment section 8E regards thevertical variation amount q of point PQ at the center of the upstreamside in the width direction as a reference to obtain a warp amount ofthe upstream side in the width direction. And then the warp statusjudgment section 8E calculates the warp amount WF_(CD) by using theaverage of the above two warp amounts as shown in the formula (B-1),where W represents the length of the width of a corrugated board sheet25, and α is a constant used to make a warp amount dimensionless.$\begin{matrix}{{WF}_{CD} = {{\frac{1}{2}\left\lbrack {\left\{ {p - \frac{a + b}{2}} \right\} + \left\{ {q - \frac{c + d}{2}} \right\}} \right\rbrack} \times \frac{\alpha}{W^{2}}}} & \left( {B\text{-}1} \right)\end{matrix}$

Further, the warp status judgment section 8E calculates a warp amountWF_(MD) in the travel direction based on the difference of the verticalvariation amount of both sheet ends PA, PD (PB, PC) in the traveldirection with respect to the center PS (PR) in the travel direction byusing the following formula (B-2). Here, the warp status judgmentsection 8E regards the vertical variation amount s of point PS at thecenter of the driving side in the travel direction as a reference toobtain a travel-direction warp amount of the driving side, regards thevertical variation amount r of point PR at the travel-direction centeron the operating side as a reference to obtain a warp amount of theoperating side in the travel direction and then calculates a warp amountWF_(MD) in the travel direction of a corrugated board sheet 25 by usingthe average of the above warp amounts as shown in the formula (B-2).$\begin{matrix}{{WF}_{MD} = {{\frac{1}{2}\left\lbrack {\left\{ {s - \frac{a + d}{2}} \right\} + \left\{ {r - \frac{b + c}{2}} \right\}} \right\rbrack} \times \frac{\alpha}{W^{2}}}} & \left( {B\text{-}2} \right)\end{matrix}$

Additionally, the warp status judgment section 8E calculates thedifference in the vertical variation amounts between two neighboringcorners (here, two corners PA and PB, and two corners PC and PD) of acorrugated board sheet 25 and calculates a twist warp amount TWF on thebasis of a ratio of the calculated difference with respect to theproduct (W×L) of the length (W) of the width direction and the length(L) of the travel direction of the corrugated board sheet 25.$\begin{matrix}{{TWF} = {\left\lbrack \frac{\left( {b - a} \right) + \left( {d - c} \right)}{2} \right\rbrack \times \frac{\alpha}{W \times L}}} & \left( {B\text{-}3} \right)\end{matrix}$

The result of the calculation is displayed on a non-illustrated displayand an operator confirms a warp status with reference to the display.

The warp detection apparatus of the thirtieth embodiment has theabove-described configuration, and warp of a corrugated board sheet 25is detected in the following manner (a manner to detect warp of thepresent embodiment) The variation sensors 7A and 7B detect verticalvariation amounts a-d and p-s respectively at the predetermined pointsPA-PD and PP-PS (the first step) and calculate amounts ofwidth-direction warp, travel-direction warp and twist warp based on thevertical variation amounts a-d and p-s (second step).

After that, on the basis of each warp type of width-direction warp,travel-direction warp and twist warp detected by the warp detectionapparatus, an operator selects one or more particular control factorsthat affect a warp type (that are able to correct warp of that type) andthe selected particular control factors and adjusts using controlvariables associated with warp amount of the warp type, such that warpof a corrugated board sheet is corrected.

Advantageously, it is possible to accurately and effectively correctwarp considering a warp amount detected by the warp detection apparatus.

A particular control factor in relation to width-direction warp is ableto adjust moisture content of a liner 20 or 23; a particular controlfactor in relation to travel-direction is able to adjusttravel-direction tension of a liner 20 or 23; and a particular controlfactor in relation to twist warp is able to adjust width-directiondistribution of a travel-direction tension of a liner 20 or 23.

(F-2) Others

The warp detection apparatus of the present invention should by no meansbe limited to the above-described thirtieth embodiment and can bemodified without departing from the gist of the present invention.

For example, the thirtieth embodiment displays the result of detectionperformed by the warp detection apparatus on a display so that anoperator confirms the result and appropriately controls one or moreparticular control factors. Alternatively, warp status informationdetected by the warp detection apparatus may be output to the processcontroller and the process controller may automatically correct warp ofa corrugated board sheet 25 on the basis of the warp status information.In this case, an operator does not have to monitor a warp status of acorrugated board sheet 25 whereupon operator work load can bediminished.

Further, vertical variation amounts a-d and p-s may be measured by thestructure shown in FIG. 68. In this example, three variation sensors 7Aare fixed to a variation sensor mounting member 372 c, which is slidablymounted on a rail 371 c horizontally extending in the travel directionof a corrugated board sheet, at an upstream side of the travel directionof a corrugated board sheet, and are arranged in the same horizontallevel along the width direction of a corrugated board sheet. Thevariation sensor mounting member 372 c includes non-illustrated drivingmeans, which drives the three variation sensors 7A, which therebyhorizontally move in the travel direction together with the variationsensor mounting member 372 c.

With such a configuration, the two edge variation sensors 7A, among thethree variation sensors 7A, measure the vertical variation c, d, r and sshown in FIG. 67 and the center variation sensor 7A measures a variationamount q. In the same manner, three variation sensors 7B are fixed to avariation sensor mounting member 372 d at downstream side of the traveldirection of a corrugated board sheet and are arranged in the samehorizontal level along the width direction of a corrugated board sheet.The two edge variation sensors 7B measure variation amounts a and bshown in FIG. 67 and the center variation sensor 7B measures a variationsensor Further, though the illustrated embodiment measures variationamounts at eight points PA-PD and PP-PS and detects width-direction warpand travel-direction warp, detection of width-direction warp can beaccomplished by measuring a vertical variation along the width directionof a corrugated board sheet. For example, width-direction warp may bedetected in a simple manner on the basis of vertical variation amountss, t, and r at the three points PS, PT and PR shown in FIG. 69 a.

In this case, an amount WF_(CD) in the width direction is calculated bythe following formula (B-4), for example. $\begin{matrix}{{WF}_{CD} = {{\frac{1}{2}\left\lbrack {\left( {t - s} \right) + \left( {t - r} \right)} \right\rbrack} \times \frac{\alpha}{W^{2}}}} & \left( {B\text{-}4} \right)\end{matrix}$

Similarly, detection of travel-direction warp can be accomplished bymeasuring a vertical variation along the travel direction of acorrugated board sheet. For example, travel-direction warp may bedetected in a simple manner on the basis of vertical variation amountsp, t, and q at the three points PP, PE and PQ shown in FIG. 69 b.

In this case, an amount WF_(MD) in the travel direction is calculated bythe following formula (B-5), for example. $\begin{matrix}{{WF}_{MD} = {{\frac{1}{2}\left\lbrack {\left( {t - p} \right) + \left( {t - q} \right)} \right\rbrack} \times \frac{\alpha}{W^{2}}}} & \left( {B\text{-}5} \right)\end{matrix}$

In the above thirtieth embodiment, the variation sensors measurevertical variations of a corrugated board sheet 25 at the stackingsection 192. Satisfactory measurement of a vertical variation isperformed on a final product of a corrugated board sheet 25, the entirewidth of which has been cut by the cut-off device 18, by the variationsensors. Namely, the satisfactory measurement is carried out downstreamof the cut-off device 18. For example, one or more variation sensors maybe arranged over a conveyer 191 in the stacker 19 so that themeasurement is performed on a corrugated board sheet being transferredon the conveyer 191.

The vertical variation amount detecting means of the thirtiethembodiment takes the form of variation sensors. Alternatively, thevertical variation amount detecting means maybe formed by a CCD camera(imaging means) and image analysis means to analyze vertical variationamounts on the basis of image data from the CCD camera, as a substitutefor variation sensors.

(G)

Hereinafter, a system for correcting possible warp of a corrugated boardsheet according to the thirty-first and thirty-second embodiments andmodifications thereof will now be described with reference to FIGS.70-75. Parts and elements identical to those described in the foregoingembodiments are to be referred to by the same reference numbers.

Embodiments of the present invention will now be described withreference to accompanying drawings.

(G-1) Thirty-First Embodiment

FIG. 71 schematically shows a system for fabricating a corrugated boardsheet according to the thirty-first embodiment of the present invention.The system for fabricating a corrugated board sheet of this embodimentcomprises a corrugated-board fabrication machine 1 and a productionmanagement machine 2F to manage the corrugated-board fabrication machine1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10F to heat a bottom liner 20, amedium web preheater 12F to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by the medium web preheater12F and then glue the medium web 21 to the bottom liner 20 heated by thebottom liner preheater 10F, a single-face web preheater 13F to heat asingle-face web 22 formed by the single facer 11, a top liner preheater14F to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13F, a double facer 16 tofabricate a corrugated board 24 by gluing the single-face web 22 pastedby the glue machine 15 to a top liner 23 heated by the top linerpreheater 14, a slitter scorer 17 to slit and score the corrugated board24 fabricated by the double facer 16, a cut-off device 18 to make afinal product (a corrugated board sheet) 25 by dividing a corrugatedboard 24 scored and subjected to another procedure by the slitter scorer17 into separated forms, and a stacker 19 to sequentially stackcorrugated board sheets 25 in a fabricated order.

The detailed structure of elements 10F, 11, 13F, 14F, 15 will behereinafter described with reference to FIGS. 72 and 73. FIG. 72schematically shows structures of the bottom liner preheater 10F, thesingle facer 11 and the medium web preheater 12F; and FIG. 73,structures of the single-face web preheater 13F, the top liner preheater14F, the glue machine 15 and a part of the double facer 16.

As shown in FIG. 72, the bottom liner preheater 10F includes bottomliner heating rolls 1101A and 1101B vertically arranged. Supplyinginside of the bottom liner heating rolls 1101A and 1101B with vaporheats the bottom liner heating rolls 1101A and 1101B to predeterminedtemperatures. A bottom liner 20 sequentially guided by guide rolls 105,104A, 106 and 104B is wrapped around the curved surfaces of the bottomliner heating rolls 1101A and 1101B, and preheated by the bottom linerheating rolls 1110A and 1101B.

Among these guide rolls 105, 104A, 106 and 104B, the guide roll 104A,which is arranged adjacent to the bottom liner heating roll 1101A, issupported by the tip of an arm 103A swingably mounted to the axis of thebottom liner heating roll 101A; and the guide roll 104B, which isarranged adjacent to the other bottom liner heating roll 1101B, issupported by the tip of an arm 103B swingably mounted on the axis of thebottom liner heating roll 1101B. Each of the arms 103A and 103B is movedto an arbitrary position within the angle range indicated by the arrowsin the accompanying drawing by a non-illustrated motor. Here, a set ofthe guide roll 104A, the arm 103A and the non-illustrated motor (seereference symbol M in FIG. 70 b), and a set of the guide roll 104B, thearm 104B and a motor, function as wrap-amount adjusting units(wrap-amount adjusting means) 102A and 102B, respectively.

With this configuration, the bottom liner preheater 10F can adjust amoisture content of a bottom liner 20, by adjusting vapor pressuresupplied to the bottom liner heating rolls 1101A and 1101B, and wrapamounts (wrap angles) of a bottom liner 20 around bottom liner heatingrolls 1101A and 1101B by the wrap-amount adjusting units 102A and 102B.Specifically, higher vapor pressure and/or the larger wrapped amountincrease heat provided to a bottom liner 20 from the bottom linerheating rolls 1101A and 1101B so that the bottom liner 20 becomes drierand thereby the moisture content thereof declines.

The single facer 11 includes a press belt 113 wrapped around a belt roll111 and a tension roll 112, an upper roll 114 having a wave-form surfaceand pressing the press belt 113 in contact with the press belt 113, anda lower roll 115 also having a wave-form surface and engaging with theupper roll 114. A bottom liner 20 heated by the bottom liner preheater10F is wrapped around a liner preheating roll 117 to be preheated andthen guided, together with the press belt 113, to a nip between thepress roll 113 and the upper roll 114 by the belt roll 111. Meanwhile, amedium web 21 heated by the medium web preheater 12 is wrapped around amedium web preheating roll 118 to be preheated, corrugated at theengaging point of the upper roll 114 and the lower roll 115, and thenguided to the nip between the press belt 113 and the upper belt 114 bythe upper roll 114.

A pasting unit 116 is disposed close to the upper roll 114. The pastingunit 116 is formed by a glue dam 116 a to store glue 30, a pasting roll116 b to apply the glue to a medium web 21 to be transferred by theupper belt 114, a meter roll 116 c to adjust a glue amount applied tothe surface of the pasting roll 116 b, a glue sweeping blade 116 d tosweep glue from the meter roll 116 c. Each flute tip of a medium web 21corrugated at the engaging point of the upper roll 114 and the lowerroll 115 is pasted by pasting roll 116 b and the medium web 21 is gluedto the bottom liner 20 at the nip between the press belt 113 and theupper roll 114 whereby a single-face web 22 is fabricated.

With this configuration, the single facer 11 can adjust a moisturecontent of a bottom liner 20 by adjusting a gap amount between thepasting roll 116 b and the upper roll 114 and the gap between thepasting roll 116 b and the meter roll 116 c. Concretely, a larger gapamount increases an amount of glue applied to each contact point of amedium web 21 with a bottom liner 20 so that water contained in the glueincreases a moisture content of the bottom liner 20. The above gapamounts can be adjusted by movement of the pasting roll 116 b and/or themeter roll 116 c.

The medium web preheater 12 is identical in configuration to the bottomliner preheater 1F, and includes a medium-web heating roll 121 to beheated to a predetermined temperature by being applied to the insidetherein with vapor, and a wrap amount adjusting unit 122 to adjust awrap amount (a wrap angle) of a medium web 21 around the medium webheating roll 121. The wrap amount adjusting unit 122 includes a guideroll 124 around which a medium web 21 is wrapped, an arm 123 swingablymounted to the axis of the medium web heating roll 121 in order tosupport the guide roll 124, and a non-illustrated motor to rotate thearm 123.

As shown in FIG. 73, the single-face web preheater 13F and the top linerpreheater 14F are vertically arranged and are identical in configurationto the above-described bottom liner preheater 11.

The single-face web preheater 13F includes a single-face web heatingroll 131 and a wrap amount adjusting unit 132. Supplying the inside ofthe single-face web heating roll 131 heats the single-face web heatingroll 131 to a predetermined temperature. A bottom liner 20, serving asone side of a single-face web 22 sequentially guided by guide rolls 135and 134, is wrapped around the curved surface of the single-face webheating roll 131 and is preheated by the single-face web heating roll131 The wrap amount adjusting unit 132 is formed by the guide roll 134,an arm 133 swingably mounted to the axis of the single-face web heatingroll 131 in order to support the guide roll 134 and a non-illustratedmotor to rotate the arm 133. The guide roll 134 is moved to an arbitraryposition within the angle range indicated by the arrows in theaccompanying drawing under control of the motor so that a wrap amount (awrap angle) of a single-face web 22 around the single-face web heatingroll 131 can be adjusted.

With such a configuration, the single-face web preheater 13F can adjusta moisture content of the bottom liner 20 by adjusting pressure of vaporto be supplied to the single-face web heating roll 131 and a wrap amount(a wrap angle) of the single-face web 22 around the single-face webheating roll 131. Specifically, a higher vapor pressure or a larger wrapamount increases a heat amount applied to the bottom liner 20 from thesingle-face web heating roll 131 so that the bottom liner 20 gets drierand the moisture content thereof declines.

The top liner preheater 14F includes a top liner heating roll 141 and awrap amount adjusting unit 142. Supplying the inside of the top linerheating roll 141 heats top liner heating roll 141 to a predeterminedtemperature. A top liner 23 sequentially guided by guide rolls 145 and144 is wrapped around the curved surface of the top liner heating roll141, and is preheated by the top liner heating roll 141.

The wrap amount adjusting unit 142 is formed by the guide roll 144, anarm 143 swingably mounted on the axis of the top liner heating roll 141in order to support the guide roll 144, and a non-illustrated motor torotate the arm 143. The guide roll 144 is moved to an arbitrary positionwithin the angle range indicated by the arrows in the accompanyingdrawing under control of the motor so that a wrap amount (a wrap angle)of a top liner 23 around the top liner heating roll 141 can be adjusted.

With such a configuration, the top liner preheater 14F can adjust amoisture content of the top liner 23 by adjusting pressure of vaporsupplied to the top liner heating roll 141 and a wrap amount (a wrapangle) of the top liner 23 around the top liner heating roll 141.Specifically, a higher vapor pressure or a larger wrap amount increasesa heat amount applied to the top liner 23 from the top liner heatingroll 141 so that the top liner 23 gets drier and the moisture contentthereof declines.

The glue machine 15 includes a pasting unit 151 and a pressure bar unit152. A single-face web 22 that has been heated by the single-face webpreheater 13 is preheated by a single-web preheating roll 155 and thenis guided into the inside of the glue machine 15 by guide rolls 153 and154. The pasting unit 151 is disposed on the lower side (themedium-web-21 side) of the travel path of a single-face web 22 betweenthe guide rolls 153 and 154 while the pressure bar unit 152 is disposedon the upper side (the bottom-liner-20 side) of the travel path.

The pasting unit 151 includes a glue dam 151 a to store glue 31, apasting roll 151 b disposed adjacent to the travel path of a single-faceweb 22, and a doctor roll 151 c being in contact with the pasting roll151 b and rotating in the opposite direction to the pasting roll 151 b.The pressure bar unit 152 is formed by a pressure bar 152 a arrangedopposite to the pasting roll 151 b with respect to the single-face web22, and an actuator 152 b to press the pressure bar 152 a towards thepasting roll 151 b. A single-face web 22 is pressed towards the pastingroll 151 b by the pressure bar 152 a, and each flute tip of the mediumweb 21 is pasted by the pasting roll 151 b when the single-face web 22passes through the space between the pressure bar 152 a and the pastingroll 151 b. A single-face web 22 having a medium web 21 flutes of whichare pasted is to be glued to a top liner 23 in the ensuing processperformed in the double facer 16.

With such a configuration, the glue machine 15 can adjust a moisturecontent of a top liner 23 by adjusting a gap amount between the pastingroll 151 b and pressure bar 152 a (i.e., a gap amount of the pastingroll 151 b in relation to the travel path of the single-face web 22).Specifically, a larger gap amount increases an amount of glue applied toeach glued contact point of a medium web 21 with a top liner 23, so thatmoisture contained in the top liner 23 increases, thereby increasingmoisture content of the top liner 23. The actuator 152 b can adjust theabove gap amount by adjusting the position of the pressure bar 152 a.

A single-face web 22 pasted in the glue machine 15 is transferred to thedouble facer 16 in which the ensuing step is to be performed. A topliner 23 heated in the top liner preheater 14 is transferred to thedouble facer 16 through the inside of the glue machine 15. During thetransfer, the top liner 23 is guided and preheated by a liner preheatingroll 156 disposed in the glue machine 15.

At the entrance of the double facer 16, a first shower unit (a bottomliner lubrication unit) 161A is disposed on the bottom-liner-20 sidealongside the travel path of a single-face web 22; and a second showerunit (a top liner lubrication unit) 161B is disposed alongside thetravel path of top liner 23. These shower units 161A and 161B arerespectively used to adjust moisture contents of bottom liner 20 and topliner 23, respectively; the shower unit 161A sprays water over a bottomliner 20 and the shower unit 161B sprays water over a top liner 23. Themoisture content of the bottom liner 20 increases in accordance with anamount of water sprayed from the shower unit 161A, and the moisturecontent of the top liner 23 increases in accordance with an amount ofwater sprayed from the shower unit 161B. These shower units 161A and161B are controlled independently of each other.

The preheaters 10F, 12F-14F have characteristic configurations in thisinvention, which configuration is illustrated by exemplifying thedescription of the bottom liner preheater 10F with reference to FIG. 70a, 70 b.

FIGS. 70 a and 70 b respectively show a configuration of a heating rollof a bottom liner preheater 10F: FIG. 70 a is a schematic sectionalfront view (seen from the web traveling direction); and FIG. 70 billustrates a manner to control a heat amount. A wrap amount adjustingunit is omitted in FIG. 70 a.

As described above, the bottom liner preheater 10F includes the heatingrolls (heating means) 1101A and 1101B. The configurations thereof aredescribed by exemplifying the heating roll 1101A. As shown in FIG. 70 a,the heating roll 1110A is formed by a plurality (two in this example) ofcylindrical shells (heating units) 107 having the same diameter andarranged in such a posture that the axes of the shells 107 forms asingle straight line in the web-width direction. In other words, theheating roll 1101A is divided into the plural shells 107 arranged in theweb-width direction.

Each of shells 107 includes axis parts 107 a and 107 b at both flat sidesurfaces and the axis parts 107 a and 107 b are supported by bearings108 so that the shell 107 can rotate. In this embodiment, movement of abottom liner (a web) wrapped around the curved surfaces of the shells107 rotates the shells 107. The bearings 108 are supported bynon-illustrated frames.

Each shell 107 has a hollow shape, into which vapor is supplied so thata bottom liner wrapping around the curved surface thereof is heated.Specifically, the outer axis part 107 a of each shell 107 is in the formof a pipe, to which a vapor pipe 109 is connected as shown in FIG. 70 b.Thereby, vapor supplied from a non-illustrated vapor source is adjustedto a predetermined pressure by a pressure adjusting valve 109 ainstalled in each vapor pipe 109 and then supplied into a correspondingshell 107.

A temperature sensor (moisture content measuring means) 110 is disposeddownstream of each shell 107 so as to face to a bottom liner 20. Aplurality of (in this example, two) temperature sensors 110, one foreach of the shells 107, are arranged in the width direction (Atemperature sensor 110 is disposed for each shell 107 in order tomeasure temperature of a portion of a web which portion is heated by theshell 107). Temperature information (information of the parametersconcerning a moisture content) obtained by the temperature sensors 110is output to the process controller 5F in the production managementmachine 2F. After that, the process controller (control means) 5Fcontrols heat amounts applied to the individual shells 107 arranged inthe web-width direction by controlling an opening degree of eachpressure adjusting valve 109 a based on the measurement result obtainedby the temperature sensors 110 such that the temperature of a bottomliner 20 becomes a predetermined value without a temperature variationin the web width direction.

The above predetermined temperature is appropriately determined by theprocess controller 5F in accordance with, for example, productioninformation.

As shown in FIG. 70 a, a drain pipe 109 b is passed into the axis part107 a of each shell 107 so that vapor applied into the inside of theshell 107 heats a bottom liner 20, becomes condensation and then isdrained through the drain pipe 109 b.

The production management machine 2F appropriately controls each of theabove elements 10F, 11 and 13F-16F, and includes, as shown in FIG. 71,the control variable calculating section 4F and the process controller5F.

The control variable calculating section 4F obtains production stateinformation from a non-illustrated upper system for productionmanagement. The control variable calculating section 4F calculates eachcontrol variable on the basis of such production state information andmachine state information (running state) obtained through the processcontroller 5F, and outputs the result of the calculation to the processcontroller 5F. The process controller 5F controls each control factor inaccordance with control instructions from the control variablecalculating section 4F. The control variable calculating section 4F andthe process controller 5F carry out matrix control using productionstate information and running state information in the above describedmanner.

The process controller 5F always grasps a current machine state of thecorrugated-board fabrication machine 1, and outputs the current machinestate to the control variable calculating section 4F regularly or inresponse to a request from the control variable calculating section 4F.The machine state information is input from the process controller 5Fthat is to be described later.

A machine state represents the current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of a web), a wrapamount of a web around each of the heating rolls 1101A, 1101B, 131 and141, vapor pressure applied to each of the heating rolls 1101A, 1101B,131 and 141, gap amounts between the rolls 116 b and 114 and between therolls 116 b and 116 c in the single facer 11, a gap amount between thepasting roll 151 b and the pressure bar 152 a in the glue machine 15,spray amounts of the shower units 161A and 161B and so on.

Each of the preheaters 10, and 12-14 of the thirty-first embodiment hasa heating roll divided into a plurality of parts arranged in theweb-width direction, so that it is possible to adjust heat amountsapplied to web-width portions of each of webs 20-23. As a result, awater content (a temperature) of each web 20-23 can be uniform in thewidth direction and width-direction S-shape warp can be inhibited whilemaintaining an optimum tension of the web 20-23 (i.e., without affectingthe web tension).

On the basis of measurements results obtained by temperature sensors,pressure adjusting valves for the shells arranged in the web-widthdirection are automatically controlled by the process controller 5F sothat, advantageously, temperature management of webs 20-23 isautomatically controlled and width-direction S-shape warp is alsoautomatically inhibited.

Adjustment of a web wrap amount around the heating rolls of eachpreheater 10, and 12-14 by a wrap amount adjusting unit can control heatamounts applied to the entire width of webs 20-23 in a lump. Thereby, ifthe entire width of a web 20-23 is higher or lower in temperature than apredetermined temperature irrespective of a region in the widthdirection, the above-described adjustment for a web wrap amount roughlyadjusts the temperature and then heat amounts applied to individualshells arranged in the web width direction are controlled whereupondetailed temperature controlling in the width direction can beeffectively performed.

In this thirty-first embodiment, rotation of heating rolls (shells) of apreheater follows traveling of a web. Alternatively, a heating roll mayinclude a driving mechanism as shown in FIG. 74. Each shell 107 thatforms a heating roll is rotated by a driving motor 200 through a gear201 fixed to the axis of the motor and a gear 202 fixed to the outersurface of the axis part 107 a of the shell 107 and engages with thegear 201. The two shells 107 are driven in synchronization (in the samerotating rate).

In the structures shown in FIGS. 70 and 74, the inner axis parts 107 bof the two shells 107 may be a shared shape commonly used by the twoshells 107.

(G-2) Thirty-Second Embodiment

FIGS. 75 a and 75 b respectively show a configuration of a heating roll1101A′ of this embodiment; FIG. 75 a is a front sectional view (seenfrom the web travel direction); and FIG. 75 b explains controlling of aheat amount. Parts and elements identical to those described in theforegoing embodiments are to be referred by the same reference numbers,and repetitious description is omitted here.

The heating roll 1101A′ is a substitute for the heating roll 1101A ofFIG. 72 and is used in the bottom liner preheater 10F. Similar to thefirst embodiment, two shells having the same diameter are arranged insuch a posture that the axes thereof form a single straight line in theweb-width direction. Each of these shells 107 and 107 is fixed to andcantilever-supported to frame 203 to form a fixed structure (so as notto rotate) through a supporting member 107 a′ arranged at an outer sidewall of the shells so that a bottom liner 20 slides on the shells 107.Supporting members 107 a′ are in the form of a pipe, through which vaporis supplied into the insides of the shells 107. A drain pipe 109 bpasses through a supporting member 107 a′ to insert into a shell 107, sothat condensed vapor is drained through the drain pipe 109 b.

As shown in FIG. 75 b, a heating roll 1101A′ of this embodiment does notinclude a wrap amount adjusting unit 102A, differently from the heatingroll 1101A of the thirty-first embodiment shown in FIG. 70 b. On thebasis of measurement results obtained by temperature sensors 110, onebeing installed for each shell 107, individual opening degrees ofpressure adjusting valves 109 a, one being installed for each shell 107,are adjusted such that the temperature of the entire width of a bottomliner 20 becomes a predetermined value.

The preheaters of the thirty-second embodiment therefore guarantee thesame advantages as those of the the thirty-first embodiment.

(G-3) Others

The preheaters of the present invention should by no means limited tothose described in the thirty-first and the thirty-second embodimentsand can be changed or modified without departing from the sprit of thepresent invention.

For example, a moisture sensor may be alternatively used as a substitutefor a temperature sensor serving as moisture content measurement meansto measure a moisture content of a web.

In the thirty-first and the thirty-second embodiments, a heat amountapplied to each shell 107 is controlled in accordance with themeasurement result obtained by a corresponding temperature sensor(moisture content measurement means). Alternatively, a CCD camera mayphotograph the travel-direction end of a corrugated board sheet 25stacked in the stacker 19 and heat amounts (opening degree of pressureadjusting valves 109 a) may be adjusted on the basis of image dataobtained by the CCD camera. In this case, a vertical variation amount(position in height) of a corrugated board sheet 25 is detected alongthe width direction thereof on the basis of image data obtained by theCCD camera and a status concerning width-direction S-shape warp of thecorrugated board sheet 25 is detected based on the detected variationamount.

Further, in the thirty-first and the thirty-second embodiments, theprocess controller 5F automatically controls the pressure adjustingvalves 109 a on the basis of information detected by the temperaturesensors (the moisture content measuring means). Alternatively, anoperator may visually observe a warp status of a corrugated board sheet25, as substitute for installation of the moisture content measuringmeans, and may manually control the pressure adjusting valves 109 a inaccordance with the observed warp status.

The thirty-first and thirty-second embodiments include preheaters eachof which is divided into two parts in the width direction.Alternatively, preheaters may be divided into two or more parts, forexample, into three parts.

Still further, a preheater may not take the form of heating rolls. Forexample, a preheater may take the form of heating boxes into which vaporis supplied and which are arranged in the width direction of a web, sothat a web may slides on these heating boxes.

Preheaters of the thirty-first and the thirty-second embodiments areheated by supplying vapor into the insides thereof. The manner to heatpreheaters should by no means be limited to vapor heating, but may bealternatively performed by dielectric heating or induction heating, forexample.

(H)

Hereinafter, an apparatus for detecting possible warp of a corrugatedboard sheet according to thirty-third to thirty-fifth embodiments andmodifications thereof will now be described with reference to FIGS.76-81. Parts and elements identical to those described in the foregoingembodiments are to be referred by the same reference numbers anddescription thereof is partially omitted.

(H-1) Thirty-Third Embodiment

A system for fabricating a corrugated board sheet of this embodimentwill now be described with reference to FIG. 78. FIG. 78 schematicallyshows a system for fabricating a corrugated board sheet.

A system for fabricating a corrugated board sheet includes acorrugated-board fabrication machine 1 and a production managementmachine 2G to manage the corrugated-board fabrication machine 1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by the medium web preheater12 and then glue the medium web 21 to the bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat thesingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste the single-faceweb 22 heated by the single-face web preheater 13, a double facer 16″ tofabricate a corrugated board 24 by gluing a single-face web 22 pasted bythe glue machine 15 to a top liner 23 heated by the top liner preheater14, a slitter scorer 17 to slit and score the corrugated board sheet 24fabricated by the double facer 16″, a cut-off device 18 to make a finalproduct (a corrugated board sheet) 25 by dividing a corrugated board 24scored and subjected to another procedure by the slitter scorer 17 intoseparated forms, and a stacker 19 to sequentially stack corrugated boardsheets 25 in the order in which they are fabricated.

The production management machine 2G appropriately controls each of theelements 10, 11, and 13-16″, and includes, as shown in FIG. 78, acontrol variable calculating section 4G, and a process controller(control means) 5G.

The control variable calculating section 4G obtains production stateinformation from a non-illustrated upper system for productionmanagement. The control variable calculating section 4G calculates eachcontrol variable on the basis of such production state information andmachine state information (running state) obtained through the processcontroller 5G, and outputs the result of the calculation to the processcontroller 5G. The process controller 5G controls each control variableresponsive to control instructions from the control variable calculatingsection 4G. The control variable calculating section 4G and the processcontroller 5G carry out matrix control using production stateinformation and running state information in the above described manner.

The process controller 5G always grasps a current machine state of thecorrugated-board fabrication machine 1, and outputs the current machinestate to the control variable calculating section 4G regularly or inresponse to a request from the control variable calculating section 4G.

A machine state represents the current values of a running speed of thecorrugated-board fabrication machine 1 (a travel rate of a web), apressing force of a later-described press unit 162 of the double facer16″, and a vapor pressure of hotplates 1162 of the double facer 16″ andso on.

A detailed structure of the double facer 16″ of the thirty-thirdembodiment will now be described.

First of all, the entire structure of the double facer 16″ is describedwith reference to FIG. 77, which schematically shows the entirestructure of the double facer 16″.

The double facer 16″ is divided into an upstream heating section 16A″and a downstream cooling section 16B″ which sections lie along thetravel path of a bottom liner 20 and a top liner 23. In the heatingsection 16A″, a plurality of hotplates 1162 are disposed along thetravel path and a plurality of press units are arranged on the hotplates1162 along the travel path. Vapor supplied to the inside of eachhotplate 1162 heats the hotplates 1162 to a predetermined temperature.

On the hotplates 1162, a loop-shape press belt 163 interposed by thetravel path runs in synchronization with a single-face web 22 and a topliner 23. A plurality of pressure units 164 are disposed in the loopformed by the press belt 163 so as to be opposite the hotplates 1162.Each of the pressure units 164 is constituted of a pressure bar 164 a incontact with the back of the press belt 163 and an air cylinder 164 b topress the pressure bar 164 a to the hotplate-1162 side. Each press unit164 has a structure to press the entire width of a single-face web 22 ora top liner 23.

A single-face web 22 pasted in the glue machine 15 (see FIG. 78) isintroduced to a space between the press belt 163 and the hotplates 1162from the press-belt-163 side (so as to be in contact with the press belt163) while a top liner 23 heated by the top liner preheater 14 isfurther preheated by the liner entrance preheating roll 165 and is thenintroduced to the space between the press belt 163 and the hotplates1162 from the hot-plates-1162 side (so as to be in contact with thehotplates 1162). After being introduced to the space between the pressbelt 163 and the hotplates 162, the single-face web 22 and the top liner23 pile up to form one body and are transferred to the cooling section16B. While the single-face web 22 and the top liner 23 are transferred,the single-face web 22 and the top liner 23 are pressed by the pressureunit 164 through the press belt 163 and are heated from the top-liner-23side so that the single-face web 22 and the top liner 23 are gluedtogether to form a double-face web 24. The overall width or the edge ofthe double-face web 24 is cut by a rotary shear installed at the exit ofthe cooling section 16B and then the double-face web 24 is transferredto the slitter scorer 17 at which the ensuing step is to be performed.

The hotplates 1162 will now be further detailed described with referenceto FIGS. 76 a and 76 b. FIGS. 76 a and 76 b schematically show the mainpart (the hotplates 1162) of the double facer 16″: FIG. 76 a is a frontsectional view (seen from the web travel direction); and FIG. 76 b is aside view thereof.

As shown in FIG. 76 a, each hotplate 1162 includes a plurality (two inthe illustrated embodiment) of heating chambers 162 arranged in theweb-width direction. In other words, each hotplate 1162 is divided inthe web-width direction into a plurality of heating chambers 162 a.

A vapor inlet 162 b is installed on one side face of each heatingchamber 162 a. A vapor pipe 162 c shown in FIG. 76 b is connected toeach vapor inlet 162 b. Vapor supplied from non-illustrated vapor sourcein order to heat a web is adjusted to a set pressure by vapor pressureadjusting valves 162 d, one disposed in each of the vapor pipes 162 band then provided to individual heating chambers 162 a.

At the exit of the heating section 16A″, temperature sensors (watercontent measuring means) 162 f are installed so as to face a top liner23. As mentioned above, each of the hotplates 1162 arranged in theweb-travel direction is divided into a plurality of forms in theweb-width direction, that is, a number of heating chambers 162 a formtwo lines in the web-travel direction. A plurality (two in this example)of the above temperature sensors 162 f are installed in the web-widthdirection and one of the temperature sensors 162 f is dedicated to eachline formed by heating chambers (i.e., temperature sensors 162 f arearranged in order to measure a temperature of a web region heated byindividual lines formed by heating chambers).

Temperature information (information of the parameters in relation tomoisture contents) from these temperature sensors 162 f is output to theprocess controller 5G of the production management machine 2G. On thebasis of results of measurement performed by temperature sensors 162 f,process controller 5G adjusts an opening degree of each vapor pressureadjusting valve 162 d to individually control heat amounts applied tothe heating chambers 162 a arranged in the web-width direction such thata single-face web 22 and a top liner 23 is heated to a predeterminedtemperature without variations in the web-width direction.

The predetermined temperature is appropriately set by the processcontroller 5G in accordance with, for example, production information.

As shown in FIG. 76 a, a drain pipe 162 e passes through each vaporinlet 162 b. Vapor in each heating chamber 162 a is condensed afterheating a single-face web 22 and a top liner 23, and drained through thedrain pipes 162 e.

Since the double facer of the thirty-third embodiment includes eachhotplate 1162 divided into a number of heating chambers 162 a arrangedin the web-width direction, it is possible to uniformly heat asingle-face web 22 and a top liner 23 by adjusting width-direction heatamounts that the hotplates 1162 apply to the single-face web 22 and thetop liner 23 whereupon width-direction S-shape warp can be inhibited.

Since the process controller 5G automatically controls the vaporpressure adjusting valves 162 d of the heating chambers 162 a, which arearranged in the web-width direction, on the basis of measurement resultsobtained by temperature sensors 162 f, it is advantageously possible toautomatically control the temperature of a single-face web 22 and a topliner 23 and to thereby automatically inhibit width-direction S-shapewarp.

(H-2) Thirty-Fourth Embodiment

FIG. 79 schematically shows a side view of a heating section 16A″according to the thirty-fourth embodiment of the present invention.Compared to the thirty-third embodiment shown in FIGS. 76 a and 76 b,the heating section 16A″ of this embodiment includes an air-pressureadjusting valve 164 d on an air pipe 164 c, through which air isprovided to air cylinders 164 b of pressure units 164. The processcontroller 5G controls the degree to which the air-pressure adjustingvalve 164 d is open, as well as those of the vapor pressure adjustingvalves 162 d for the hotplates 1162, based on results obtained bymeasurement of the temperature sensors 162 f such that the temperatureof a single-face web 22 and a top liner 23 becomes a predeterminedtemperature. Controlling the air-pressure adjusting valve 164 d cancollectively control pressures and also heat amounts that are applied tothe entire single-face web 22 and top liner 23 by press bars 164 a,which are arranged so as to cover the entire width of the single-faceweb 22 and the top liner 23.

As described above, the double facer of the thirty-fourth embodiment cancollectively control a heat amount applied to heat the entire width of asingle-face web 22 and a top liner 23 by controlling pressures appliedby the press units 164. Therefore, if the entire width of a single-faceweb 22 and a top liner 23 is higher or lower in temperature than apredetermined temperature irrespective of a region in the widthdirection, controlling pressures applied by the press units 164 roughlyadjust the temperature and then heat amounts applied to the individualheat chambers 162 a arranged in the web width direction are controlledwhereupon detailed temperature controlling in the width direction can beeffectively performed.

(H-3) Thirty-Fifth Embodiment

FIG. 80 is a sectional diagram schematically showing a front view of adouble facer according to the thirty-fifth embodiment of the presentinvention. In the heating section thereof, similarly to the foregoingembodiments, hotplates 1162, each of which is divided into a plurality(two in this example) of heating chambers 162 a arranged in the webwidth direction, are vertically disposed and are interposed by thetravel path for a single-face web 22 and a top liner 23. The press units164 in the thirty-third embodiment shown in FIGS. 76 a and 76 b aresubstituted by the hotplates 1162 in this embodiment. A single-face web22 and a top liner 23 travel in contact with the hotplates 1164 arrangedon and beneath the webs (FIG. 80 illustrates a single-face web 22 and atop liner 23 departing from each other, for convenience). The remainingconfiguration is identical to that of the thirty-third embodiment, soany repetitious description is omitted here.

The double facer of the thirty-fifth embodiment can inhibit atemperature variation in the web width direction from both sides of asingle-face web 22 and a top liner 23 by using the hotplates 1162 sothat it is advantageously possible to further effectively inhibitS-shape warp.

(H-4) Others

The double facer of this invention should by no means be limited thosedescribed in the thirty-third to the thirty-fifth embodiments andvarious changes and modifications can be suggested without departingfrom the concept of the present invention.

For example, an example shown in FIG. 76 b includes vapor pressureadjusting valves 162, one for each of the heating chambers 162 a, inorder to control heat amounts applied to the individual heat chambers162 a. Sufficient control over a heat amount using the heating chambers162 a may be individually performed for different positions in relationto the width direction of a web. Alternatively, for this reason, onevapor pressure adjusting valve 162 d may be applied to each line(chamber line) formed by heating chambers 162 a arranged in the webtravel direction, so that a heat amount applied to each chamber line andthereby a heat amount applied to the width direction of a web arecontrolled.

In the thirty-third to the thirty-fifth embodiments, the moisturecontent measurement means (temperature sensors) faces a top liner 23but, alternatively, may face a single-face web 22. Further, temperaturesensors serving as the moisture content measurement means may besubstituted by moisture sensors to measure a water content of asingle-face web 22 or a top liner 23.

In the thirty-third to the thirty-fifth embodiments, heat amountsapplied to the heating chambers 162 a are controlled on the basis ofresults of measurement by temperature sensors (moisture contentmeasurement means). Alternatively, a CCD camera may photograph a traveldirection edge of a corrugated board sheet 25 (an edge along a widedirection of a corrugated board sheet 25) stacked in the stacker 19 andheat amounts applied to the heating chambers 162 a (opening degree ofthe vapor pressure adjusting valve 162 d) are controlled based on theimage data obtained by the CCD camera. In this case, a verticalvariation amount (position in height) along the width direction isdetected based on image data of the CCD camera and width-directionS-shape warp of the corrugated board sheet 25 is detected based on thevertical variation.

Further, the process controller (control means) 5G of the thirty-thirdto the thirty-fifth embodiments automatically controls the vaporpressure adjusting valve 162 d or the air pressure adjusting valve 164 dbased on a result of measurement by temperature sensors (the moisturecontent detecting means). Alternatively, an operator may visuallyobserve a warp status of a corrugated board sheet 25, as substituteinstallation of the moisture content measuring means, and may manuallycontrol the vapor pressure adjusting valve 162 d or the air pressureadjusting valve 164 d in accordance with the observed warp status.

Still further, each hotplate 1162 in the thirty-third to thethirty-fifth embodiments is divided into two parts in the widthdirection. A satisfactory hotplate 1162 is divided into a number ofparts, and for example, each hotplate 1162 may be divided into threeparts as shown in FIG. 81.

The hotplates 1162 of the thirty-third to the thirty-fifth embodimentsare heated by supplying vapor into the insides thereof. A heating mannershould by no means be limited to vapor heating, but may be alternativelyperformed by dielectric heating or induction heating.

(I)

Hereinafter, a corrugated-board sheet counter according to thethirty-sixth to thirty-eighth embodiments and modifications thereof ofthe present invention will now be described with reference to FIGS.82-85. Parts and elements identical to those described in the foregoingembodiments are to be referred to by the same reference numbers, anddescription is partially omitted here.

(I-1) Thirty-Sixth Embodiment

FIG. 82 schematically shows a system for fabricating a corrugated boardsheet according to the thirty-sixth embodiment of the present invention.First of all, description is made in relation to a system forfabricating a corrugated board sheet which incorporates acorrugated-board sheet counter 230 of the thirty-sixth embodiment.

A system for fabricating a corrugated board sheet of this embodimentincludes a corrugated-board fabrication machine 1 and a productionmanagement machine 2H to manage the corrugated-board fabrication machine1.

The corrugated-board fabrication machine 1 includes, as the mainelements, a bottom liner preheater 10 to heat a bottom liner 20, amedium web preheater 12 to heat a medium web 21, a single facer 11 tocorrugate and paste the medium web 21 heated by the medium web preheater12 and then glue the medium web 21 to the bottom liner 20 heated by thebottom liner preheater 10, a single-face web preheater 13 to heat asingle-face web 22 formed by the single facer 11, a top liner preheater14 to heat a top liner 23, a glue machine 15 to paste a single-face web22 heated by the single-face web preheater 13, a double facer 16 tofabricate the corrugated board 24 by gluing a single-face web 22 pastedby the glue machine 15 to the top liner 23 heated by the top linerpreheater 14, a slitter scorer 17 to slit and score a corrugated board24 fabricated by the double facer 16, a cut-off device 18 to make afinal product (a corrugated board sheet) 25 by dividing a corrugatedboard 24 scored and subjected to another procedure by the slitter scorer17 into separated forms, and a stacker 19 to sequentially stackcorrugated board sheets 25 in order of fabrication.

The production management machine 2H appropriately controls each of theelements 10, 11, and 13-16, and includes, as shown in FIG. 82, a controlvariable calculating section 4H and a process controller 5H.

The control variable calculating section 4H obtains production-stateinformation from a non-illustrated upper system for productionmanagement. The control variable calculating section 4H calculates eachcontrol variable on the basis of such production state information andmachine state information (running state) obtained through the processcontroller 5H, and outputs control instructions in the form of theresult of the calculation to the process controller 5H. The processcontroller 5H controls each control variable in accordance with thecontrol instructions from the control variable calculating section 4H.The control variable calculating section 4H and the process controller5H carry out matrix control using production-state information andrunning-state information.

Here, the corrugated-board sheet counter of this embodiment will now bedescribed with reference to FIG. 83 and FIG. 15 a previously used asdescription of the eighth embodiment. FIG. 83 shows a configuration ofimaging means of the corrugated-board sheet counter of this embodimentand is a detailed diagram schematically enlarging the Y-part of FIG. 15a.

The corrugated-board sheet counter 230 of this embodiment includes a CCDcamera (imaging means) 231 disposed in the stacking section 192 of thestacker 19 and an image analysis apparatus 232. The CCD camera 231 ismovably attached to a rail 192 a vertically installed in the stackingsection 192 and includes a non-illustrated driving mechanism. Corrugatedboard sheets 25 that have been cut in the cut-off device 18 aretransferred to the stacking section 192 by a plurality of conveyers 191and then subsequently piled in the stacking section 192. The CCD camera231 moves on the rail 192 a and photographs width-direction edges (edgesalong the travel direction of the corrugated board sheet 20 and asurface exposing flutes of each medium web 21) of such piled corrugatedboard sheets 20 along the direction in which the corrugated board sheetsare piled.

The image data (the image) obtained by the CCD camera 231 is output tothe image analysis apparatus 232. Information (flute information) abouta flute of a corrugated board sheet 20 being fabricated is input to theimage analysis apparatus 232 from the production management machine 2H(or by an operator via a non-illustrated inputting device). The imageanalysis apparatus 232 analyzes the above image based on the fluteinformation and recognizes the individual corrugated board sheets 20 inthe image to count the number of corrugated board sheets one by one.

Specifically, in order to recognize corrugated board sheets 20, forexample, the height and the pitch of a flute (a wave) are input as fluteinformation. Then the image analysis apparatus 232 creates an image of aflute shape on the basis of the flute information and if an imageobtained by the CCD camera 231 includes a portion identical to the fluteshape in the created image, the image analysis apparatus 232 recognizesthe identical portion as a corrugated board sheet. Otherwise, theproduction management machine 2H may previously retain, as fluteinformation, images of various flutes of a width direction edge and theflute information may be output to the image analysis apparatus 232 asrequired.

The counted number of corrugated board sheets is displayed on anon-illustrated display.

The corrugated-board sheet counter of the thirty-sixth embodiment hasthe above-described structure and can count the accurate number ofcorrugated board sheets by analyzing image data obtained by the CCDcamera. Advantageously, it is thereby possible to accurately manageproduction of corrugated board sheets.

A count of corrugated board sheets is performed at the stacking section192 that is the rearmost part of the corrugated-board fabricationmachine. Since, even if one or more defective corrugated board sheets 20have been removed during the production process, the number ofcorrugated board sheets except the number of removed corrugated boardsheets, i.e., the number of final products, can be accurately counted,it is also possible to accurately manage production of corrugated boardsheets.

I-2) Thirty-Seventh Embodiment

A corrugated-board sheet counter according to a thirty-seventhembodiment will now be described with reference to FIG. 84, whichschematically shows the corrugated-board sheet counter of thisembodiment and corresponds to FIG. 83.

The corrugated-board sheet counter of this embodiment includes avariation sensor 233 and a calculating apparatus (number calculatingmeans) 234.

The variation sensor 233 is disposed beneath the ceiling surface 192 bof the stacking section 192 and measures vertical variation (hereinafteralso called measured data) X, i.e., distance between the sensor surface233 a thereof and the top corrugated board sheet 20 piled in thestacking section 192.

The measured data X obtained by the variation sensor 233 is output tothe calculating apparatus 234. The calculating apparatus 234 previouslyretains the distance H0 between the sensor surface 233 a and a floor 192c of the stacking section 192, and obtains a height H of sheets usingthe difference between the measured data X and the distance H0 (H=H0−X).The combination of the variation sensor 233 and the calculatingapparatus 234 therefore serves as the height measuring means of thepresent invention.

The calculating apparatus 234 also functions as the calculating means ofthe present invention. The production management machine 2H inputs athickness ts per corrugated board sheet 20 currently being fabricated tothe calculating apparatus 234 (otherwise, an operator inputs thethickness via a non-illustrated input device) and the calculatingapparatus 234 divides the height H by the thickness ts to calculate thenumber N of corrugated board sheets (N=H/ts).

The corrugated-board sheet counter of the thirty-seventh embodiment hasthe above-mentioned structure and thereby can guarantee the sameadvantages as the thirty-sixth embodiment.

(I-3) Thirty-Eighth Embodiment

A corrugated-board sheet counter according to a thirty-eighth embodimentwill now be described with reference to FIG. 85, which schematicallyshows the corrugated-board sheet counter of this embodiment andcorresponds to FIG. 83.

The corrugated-board sheet counter of this embodiment includes avariation sensor 233 and a calculating apparatus (number calculatingmeans) 234′. The variation sensor 233 is disposed beneath the ceilingsurface 192 b of the stacking section 192 and measures the distance Xbetween the sensor surface 233 a thereof and the top corrugated boardsheet 20 piled in the stacking section 192 in the same manner as theabove thirty-seventh embodiment.

The measured data obtained by the variation sensor 233 is output to thecalculating apparatus 234′. The calculating apparatus 234′on/off-detects whether or not the measured data X decreases as comparedto the previous detection, in other words, whether or not a height H ofthe sheets increased. When an increase in sheet height H of the sheetsis detected, the calculating apparatus 234′ judges that anothercorrugated board sheet 20 has been piled in the stacker 19 and increasesthe count number N of corrugated board sheets in increments of one(N=N+1).

Additionally, when the measured distance X is identical to the distanceHO to the floor 192 c of the stacking section 192, the calculatingapparatus 234′ judges that no corrugated board sheet 20 is piled in thestacking section 192 and resets the count number N of corrugated boardsheets to zero. Whereby, the count number N of corrugated board sheetsis automatically reset to zero each time piled corrugated board sheetsare taken out of the stacking section 192.

In the above example, the calculating apparatus 234′ increases thenumber N of corrugated board sheets whenever sheet height H in thestacking section 192 increases. Alternatively, the calculating apparatus234′ may increase the corrugated-board sheet number N when a variationscale

X (an absolute value) in measured data X as compared to the previousdetection is equal to or larger than a predetermined value, so that thecorrugated-board sheet number is not unnecessarily increased in responseto a variance in height detection. Of course, the predetermined value βis smaller than the thickness ts of an individual corrugated board sheet(β<ts).

Since the corrugated-board sheet counter of the thirty-eighth embodimenthas the above-described configuration, the number X of corrugated boardsheets is counted up each time a corrugated board sheet 20 beingindividually transferred is piled in the stacking section 192 andguarantees the same advantages as the foregoing embodiments.

Further, since calculation for the corrugated-board sheet numberrequires no information about flute specification and flute thickness,it is advantageously possible to simplify the control system as comparedto those of the foregoing embodiments.

(I-4) Others

The corrugated-board sheet counter of corrugated-board fabricationmachine 1 of this invention should by no means be limited thosedescribed in the thirty-sixth to the thirty-eighth embodiments andvarious changes and modifications can be suggested without departingfrom the concept of the present invention.

For example, the corrugated-board sheet counter of each embodiment mayadditionally comprise a label printer 340 to print the number N ofcorrugated board sheets together with a production date (thecorrugated-board sheet number printing means), as shown by thetwo-dotted lines in FIGS. 83-85. With this printer, productionmanagement can be carried out more easily.

Each of the corrugated-board sheet counters 230 of the thirty-sixth tothirty-eighth embodiment counts the number of double-faced corrugatedboard sheets. It is possible to apply the corrugated-board sheetcounters of the present invention to count single-faced corrugated boardsheets.

1. A system for correcting warp of a corrugated board sheet fabricatedby a corrugated-board fabrication machine (1), comprising: warp statusinformation obtaining means (6, 6A-6H, 7, 7A, 7B, 8, 8A-8H, 240 a, 240b, 241 a, 241 b) for obtaining warp status information concerning statusof the warp of the corrugated board sheet fabricated by thecorrugated-board fabrication machine (1); running-state informationobtaining means (5, 5A-5H) for obtaining running state informationconcerning a running state of the corrugated-board fabrication machine(1); control variable calculating means (4, 4A-4H) for calculating acontrol variable of a particular control factor that affects the warp ofthe corrugated board sheet and that is one among control factors used tocontrol the corrugated-board fabrication machine (1) based on the warpstatus information of the corrugated board sheet and the running stateinformation of the corrugated-board fabrication machine (1); and controlmeans (5, 5A-5H) for controlling the particular control factor using thecontrol variable calculated by said control variable calculating means(4, 4A-4H).
 2. A system for correcting warp of a corrugated board sheetaccording to claim 1, further comprising control factor selecting means(3, 3A-3H, 4, 4A-4H) for selecting at least one particular controlfactor from a plurality of particular control factors that affect thewarp of the corrugated board sheet in accordance with the warp statusinformation of the corrugated board sheet and an influence of each ofsaid plurality of particular control factors on the warp, said controlvariable calculating means (4, 4A-4H) calculating a control variable ofthe particular control factor selected by said control factor selectingmeans (3, 3A-3H, 4, 4A-4H), said control means (5, 5A-5H) controllingthe selected particular control factor using the control variablecalculated by said calculating means (4, 4A-4H).
 3. A system forcorrecting warp of a corrugated board sheet according to claim 1 or 2,wherein: the status of the warp concerns warp of the corrugated boardsheet in a direction across the width of the corrugated board sheet; andthe particular control factor is a control factor that affects amoisture content of a bottom liner (20) or a top liner (23).
 4. A systemfor correcting warp of a corrugated board sheet according to claim 1 or2, wherein said warp status information obtaining means includesmoisture content measuring means (240 a, 240 b, 241 a, 241 b) formeasuring moisture contents of a bottom liner (20) and a top liner (23),or parameters correlate with the moisture contents, and detection means(8 c) for detecting the warp of the corrugated board sheet on the basisof data obtained by said moisture content measuring means (240 a, 240 b,241 a, 241 b), and said warp status information obtaining means regardsdata obtained by said detection means (8 c) as the warp statusinformation.
 5. A system for correcting warp of a corrugated board sheetaccording to claim 1 or 2, wherein: the status of the warp concerns warpof the corrugated board sheet in a direction of travel of the corrugatedboard sheet; and the particular control factor is a control factor thataffects tension acts upon a bottom liner (20) or a top liner (23) in thedirection of travel.
 6. A system for correcting warp of a corrugatedboard sheet according to claim 1 or 2, wherein: the status of the warpconcerns twist warp of the corrugated board sheet; and the particularcontrol factor is a control factor that affects a distribution oftension acts upon a bottom liner (20) or a top liner (23) in thedirection of travel of the corrugated board sheet, which distributionconcerns a direction across the width of the corrugated board sheet. 7.A system for fabricating a corrugated board sheet comprising:running-state information obtaining means (5D) for obtaining runningstate information concerning a running state of a corrugated-boardfabrication machine (1); production-state information obtaining means(4D) for obtaining production state information concerning a productionstate in the corrugation-board fabrication machine (1); control variablecalculating means (4D) for calculating a control variable of each ofcontrol factors used to control the corrugation-board fabricationmachine (1) based on the running state information obtained by saidrunning-state obtaining means (5D) and the production state informationobtained by said production-state information obtaining means (4D);quality information detecting means (5Db) for detecting that thecorrugated board sheet fabricated by the corrugated-board fabricationmachine (1) satisfies a predetermined quality; optimum running-conditioninformation retaining means (5Da) for retaining, if said qualityinformation detecting means detects that the corrugated board sheetsatisfies the predetermined quality, a portion of the running stateinformation obtained by said running-state information obtaining means(SD) which portion is associated with a particular control factor thataffects the predetermined quality, so that the portion of therunning-state information serves as optimum running-conditioninformation concerning an optimum running condition of thecorrugated-board fabrication machine when said quality informationdetecting means detects that the corrugated board sheet satisfies thepredetermined quality; and control means (5D) for preferentiallycontrolling, if the optimum running condition information retained insaid optimum running-condition information retaining means (5Da) iscorresponding to a current production state, the particular controlfactor so as to become in the optimum running condition.
 8. A warpdetection apparatus for detecting an amount of warp of a corrugatedboard sheet fabricated in a corrugated-board fabrication machine (1),comprising: variation amount detecting means (7A, 7B) for detecting anamount of vertical variation of the corrugated board sheet in adirection of travel of the corrugated board sheet; and warp amountcalculating means (8E) for calculating an amount of the warp in thedirection of travel on the basis of the amount of vertical variationdetected by said variation amount detecting means (7A, 7B).
 9. A warpdetection apparatus for detecting an amount of warp of a corrugatedboard sheet fabricated in a corrugated-board fabrication machine (1),comprising: variation amount detecting means (7A, 7B) for detectingamounts of vertical variation at the four corners (PA-PD) of thecorrugated board sheet; and warp amount calculating means (8E) forcalculating an amount of twist warp of the corrugated board sheet on thebasis of the amounts of vertical variation detected by the variationamount detecting means (7A, 7B).
 10. A warp detection apparatus fordetecting an amount of warp of a corrugated board sheet fabricated in acorrugated-board fabrication machine (1), comprising: variation amountdetecting means (7A, 7B) for detecting amounts of vertical variation atthe four corners (PA-PD) and at the center points (PP-PS) of the foursides of the corrugated board sheet; and warp amount calculating meansfor calculating amounts of warp in a direction across a width, warp in adirection of travel, and twist warp of the corrugated board sheet on thebasis of the amounts of vertical variation detected by said variationamount detecting means (7A, 7B).
 11. A preheater, included in acorrugated-board fabrication machine (1), for heating a web (20-23),which is to be made into a corrugated board sheet by gluing the web(20-23) to a web (20-23) in a corrugated-board fabrication process,prior to the gluing using heating means (101A) including a plurality ofheating units (107) arranged in a direction across a width of the firstweb (20-23) and being operable to adjust an amount of heat to be appliedto the first web (20-23) by each of said plurality of heating units(107).
 12. A double facer for fabricating a double-face corrugated boardsheet by gluing a single-face web (22) and a top liner (23) while thesingle-face web (22) and the top liner (23) are sliding on a hotplate(1162), wherein said hot plate (1162) includes a plurality of heatingchambers (162 a) arranged in a direction across a width of thesingle-face web (22) and is operable to adjust an amount of heat to beapplied to the single-face web (22) and the top liner (23) by each ofsaid plurality of heating chambers (162 a).
 13. A counter for countingthe number of corrugated board sheets fabricated in a corrugated-boardfabrication machine (1), comprising: imaging means (231) for imagingedges of the corrugated board sheets stacked in a stack section (19)which edges are along a direction of the travel of the corrugated boardsheets; and image analysis means (232) for counting the number ofcorrugated board sheets by analyzing image data obtained by said imagingmeans (231) and recognizing each of the corrugated board sheets on thebasis of a specification for flute of medium webs of the corrugatedboard sheets.
 14. A counter for counting the number of corrugated boardsheets fabricated in a corrugated-board fabrication machine (1),comprising: height measuring means (233) for measuring a height (H) ofthe corrugated board sheets stacked in a stack section (19); and numbercalculating means (234) for calculating the number of corrugated boardsheets on the basis of the height (H) measured by said height measuringmeans (233) and a thickness (ts) per corrugated board sheet.
 15. Acounter for counting the number of corrugated board sheets fabricated ina corrugated-board fabrication machine (1), comprising: height measuringmeans (233) for measuring a height (H) of the corrugated board sheetsstacked in a stack section (19); and number calculating means (234′) forcounting the number of corrugated board sheets by increasing the numbereach time the height (H) measured by the height measuring means (233)increases as compared to the previous height measurement.